- Description
- Reviews
- Shipping and Refund
The ARM 6" B58 Downpipe is one of the foundational upgrades for giving your B58-powered BMW more power, torque, and sound. The stock B58 downpipe comes from the factory with a catalyst that severely restricts exhaust flow, causing excessive backpressure with increased boost. Upgrading to the ARM 6" B58 Downpipe unlocks power, improves turbo spool, allows you to safely run stage 2+ tuning, all while improving the sound of your B58-powered BMW.
The ARM 6" B58 Catted Downpipe is perfect if you're looking for all of the performance of a Catless B58 Downpipe without the odor associated with increased emissions. Our B58 Catted Downpipe design incorporates a 6" high-flow 200 cell ceramic catalytic converter, making it a standout choice for those seeking power without while reducing emissions. The increased volume and improved turbo spool that from the catless variations are still present in our 6" B58 Catted Downpipe.
If You are interested in 5" B58 Downpipe then look here
The ARM 6" Catted B58 Downpipe replaces the restrictive factory downpipe with a 200 cell catalyst with a 6" diameter that significantly improves exhaust flow. This upgrade unlocks additional power and torque while reducing emissions compared to a full catless B58 downpipe, allowing you to safely run Stage 2+ tunes and enjoy a more vibrant sound from your B58-powered BMW.
Highlights
- 6" 200 Cell High-Flow Catalyst
- Improved Exhaust Sound
- Faster Turbo Spool
- Stage 2+ Tune Compatibility
ENHANCE THE SOUND OF YOUR B58
The ARM 6" B58 Catted Downpipe amplifies the overall volume of your B58's exhaust, bringing out the burbles and enhancing the audible presence of the turbo spool, even on the OEM tune. Below is a sound clip of the ARM 6" Catless Downpipe, paired with our B58 Midpipe, and Single Exit Exhaust.
CONSTRUCTION
The ARM 6" B58 Catted Downpipe starts with a 4.5" diameter precision CNC machined turbo V-band flange which matches up perfectly to the OEM turbo or upgraded turbo with an OEM flange. It then rapidly transitions to the 6" OD high-flow catted section.

The ARM 6" B58 Catted Downpipe features two O2 sensor bungs to allow for reinstallation of the OEM oxygen sensors. The pre-catalyst O2 sensor bung is located closer to the turbo on the ARM 6" B58 Downpipe to avoid stretching the O2 sensor wires during installation. The post-catalyst O2 sensor bung comes with a built-in extension to allow the sensor to reach around the 6" section of the downpipe.

The ARM 6" B58 Downpipe then reduces to the OEM size to allow it to connect to the OEM midpipe or the ARM B58 Midpipe Upgrade. The flex section is incorporated into the ARM 6" B58 Downpipe to relieve stress on the turbo during aggressive driving.

The ARM 6" B58 Downpipe is further secured by the 2-bolt bracket which utilizes the OEM downpipe mounting points.
Fitment
- 2019+ G20, G22 & G26 BMW M340i & M440i & xDrive
- 2019+ F22 BMW M240i & xDrive
- 2021+ G42 BMW M240i & xDrive
- 2019+ G05 BMW X5 40i & xDrive
- 2019+ G29 BMW Z4 M40i
- 2019+ G14/G15/G16 840i & xDrive
- 2019+ G14/G15/G16 840i & xDrive
- 2016+ F22/F23 BMW M240i & M240i xDrive
- 2016+ F30/F31 BMW 340i & 340i xDrive
- 2016+ F32/F33/F36 BMW 440i & 440i xDrive
- 2016+ G30 BMW 540i & 540i xDrive
- 2016+ G32 GT BMW 640i & 640i xDrive
- 2016+ G11/G12 BMW 740i & 740i xDrive
- 2020+ Supra A90/A91 3.0T
Every ARM Motorsports product is backed by a lifetime warranty which is automatically issued at the time of purchase. Your warranty protects you against any defects in craftsmanship or fitment. The warranty entitles you to a replacement unit.
Handling
Orders shipped directly from our warehouse are usually processed the same business day if placed before 12 PM MST, and tracking details are provided within 1 business day.
For drop-shipped items, processing times may vary depending on the manufacturer, typically 3–5 business days. Tracking updates may take longer in such cases.
Expedited shipping applies only once the item is ready to ship.
Return
You have 30 days after receiving your order to request a return. Items must be unused, in original packaging, and include proof of purchase. Customers are responsible for covering the return shipping costs.
To start a return, email us at sales@palenonperformance.com. Returns sent without approval will not be accepted.
You can request a return directly from your account by selecting the return option on your order page. Here is the URL: https://shopify.com/55092379855/account/orders
Non-returnable items:
- Burger Motorsports (BMS) products
- Used items
- Air Intakes
- Hazardous materials, flammable liquids, or gases
- Discounted items and gift cards other than "PALENON PERFORMANCE" brand
Exchanges
Return the item and place a new order once approved.
Refunds
Approved refunds are issued to the original payment method. A restocking fee is 20% will be applied. Processing time depends on your bank or payment provider. The original shipping cost will not be refunded.
Cancellations
Canceled orders are subject to a 5% merchant fee (8% for Shop Pay installments). Custom, specialized items or pre-order items canceled within their lead time are also subject to this fee. Will also incur a 10% restocking fee.
Damaged or incorrect items
Inspect your order upon arrival and contact us immediately for assistance. If the wrong part was ordered, customer covers return shipping.
Disputes / Chargebacks
Our legal team is fully prepared to take stringent action against you for filing a baseless claim and initiating a fraudulent chargeback. This will lead to civil or criminal proceedings, which would require you to engage with our attorneys in our jurisdiction.
It is crucial to understand that filing a false chargeback is a serious offense, punishable by substantial fines or imprisonment. Potential penalties for fraudulent chargebacks can include one to three years in prison and fines ranging from $1,000 to $10,000. We treat all chargebacks with the utmost seriousness, regardless of the amount, as this is classified as a felony.
We will compose all necessary information to send your account to a collections agency and request that you be served once our lawyers organize the evidence and file a case against you.
The ARM 6" B58 Downpipe is one of the foundational upgrades for giving your B58-powered BMW more power, torque, and sound. The stock B58 downpipe comes from the factory with a catalyst that severely restricts exhaust flow, causing excessive backpressure with increased boost. Upgrading to the ARM 6" B58 Downpipe unlocks power, improves turbo spool, allows you to safely run stage 2+ tuning, all while improving the sound of your B58-powered BMW.
The ARM 6" B58 Catted Downpipe is perfect if you're looking for all of the performance of a Catless B58 Downpipe without the odor associated with increased emissions. Our B58 Catted Downpipe design incorporates a 6" high-flow 200 cell ceramic catalytic converter, making it a standout choice for those seeking power without while reducing emissions. The increased volume and improved turbo spool that from the catless variations are still present in our 6" B58 Catted Downpipe.
If You are interested in 5" B58 Downpipe then look here
The ARM 6" Catted B58 Downpipe replaces the restrictive factory downpipe with a 200 cell catalyst with a 6" diameter that significantly improves exhaust flow. This upgrade unlocks additional power and torque while reducing emissions compared to a full catless B58 downpipe, allowing you to safely run Stage 2+ tunes and enjoy a more vibrant sound from your B58-powered BMW.
Highlights
- 6" 200 Cell High-Flow Catalyst
- Improved Exhaust Sound
- Faster Turbo Spool
- Stage 2+ Tune Compatibility
ENHANCE THE SOUND OF YOUR B58
The ARM 6" B58 Catted Downpipe amplifies the overall volume of your B58's exhaust, bringing out the burbles and enhancing the audible presence of the turbo spool, even on the OEM tune. Below is a sound clip of the ARM 6" Catless Downpipe, paired with our B58 Midpipe, and Single Exit Exhaust.
CONSTRUCTION
The ARM 6" B58 Catted Downpipe starts with a 4.5" diameter precision CNC machined turbo V-band flange which matches up perfectly to the OEM turbo or upgraded turbo with an OEM flange. It then rapidly transitions to the 6" OD high-flow catted section.

The ARM 6" B58 Catted Downpipe features two O2 sensor bungs to allow for reinstallation of the OEM oxygen sensors. The pre-catalyst O2 sensor bung is located closer to the turbo on the ARM 6" B58 Downpipe to avoid stretching the O2 sensor wires during installation. The post-catalyst O2 sensor bung comes with a built-in extension to allow the sensor to reach around the 6" section of the downpipe.

The ARM 6" B58 Downpipe then reduces to the OEM size to allow it to connect to the OEM midpipe or the ARM B58 Midpipe Upgrade. The flex section is incorporated into the ARM 6" B58 Downpipe to relieve stress on the turbo during aggressive driving.

The ARM 6" B58 Downpipe is further secured by the 2-bolt bracket which utilizes the OEM downpipe mounting points.
Fitment
- 2019+ G20, G22 & G26 BMW M340i & M440i & xDrive
- 2019+ F22 BMW M240i & xDrive
- 2021+ G42 BMW M240i & xDrive
- 2019+ G05 BMW X5 40i & xDrive
- 2019+ G29 BMW Z4 M40i
- 2019+ G14/G15/G16 840i & xDrive
- 2019+ G14/G15/G16 840i & xDrive
- 2016+ F22/F23 BMW M240i & M240i xDrive
- 2016+ F30/F31 BMW 340i & 340i xDrive
- 2016+ F32/F33/F36 BMW 440i & 440i xDrive
- 2016+ G30 BMW 540i & 540i xDrive
- 2016+ G32 GT BMW 640i & 640i xDrive
- 2016+ G11/G12 BMW 740i & 740i xDrive
- 2020+ Supra A90/A91 3.0T
Every ARM Motorsports product is backed by a lifetime warranty which is automatically issued at the time of purchase. Your warranty protects you against any defects in craftsmanship or fitment. The warranty entitles you to a replacement unit.
Handling
Orders shipped directly from our warehouse are usually processed the same business day if placed before 12 PM MST, and tracking details are provided within 1 business day.
For drop-shipped items, processing times may vary depending on the manufacturer, typically 3–5 business days. Tracking updates may take longer in such cases.
Expedited shipping applies only once the item is ready to ship.
Return
You have 30 days after receiving your order to request a return. Items must be unused, in original packaging, and include proof of purchase. Customers are responsible for covering the return shipping costs.
To start a return, email us at sales@palenonperformance.com. Returns sent without approval will not be accepted.
You can request a return directly from your account by selecting the return option on your order page. Here is the URL: https://shopify.com/55092379855/account/orders
Non-returnable items:
- Burger Motorsports (BMS) products
- Used items
- Air Intakes
- Hazardous materials, flammable liquids, or gases
- Discounted items and gift cards other than "PALENON PERFORMANCE" brand
Exchanges
Return the item and place a new order once approved.
Refunds
Approved refunds are issued to the original payment method. A restocking fee is 20% will be applied. Processing time depends on your bank or payment provider. The original shipping cost will not be refunded.
Cancellations
Canceled orders are subject to a 5% merchant fee (8% for Shop Pay installments). Custom, specialized items or pre-order items canceled within their lead time are also subject to this fee. Will also incur a 10% restocking fee.
Damaged or incorrect items
Inspect your order upon arrival and contact us immediately for assistance. If the wrong part was ordered, customer covers return shipping.
Disputes / Chargebacks
Our legal team is fully prepared to take stringent action against you for filing a baseless claim and initiating a fraudulent chargeback. This will lead to civil or criminal proceedings, which would require you to engage with our attorneys in our jurisdiction.
It is crucial to understand that filing a false chargeback is a serious offense, punishable by substantial fines or imprisonment. Potential penalties for fraudulent chargebacks can include one to three years in prison and fines ranging from $1,000 to $10,000. We treat all chargebacks with the utmost seriousness, regardless of the amount, as this is classified as a felony.
We will compose all necessary information to send your account to a collections agency and request that you be served once our lawyers organize the evidence and file a case against you.

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