ARM S55 3.5" Resonated Single Midpipe Upgrade - F80 M3 | F82 / F83 M4
ARM S55 3.5" Resonated Single Midpipe Upgrade - F80 M3 | F82 / F83 M4
ARM S55 3.5" Resonated Single Midpipe Upgrade - F80 M3 | F82 / F83 M4
ARM S55 3.5" Resonated Single Midpipe Upgrade - F80 M3 | F82 / F83 M4
ARM S55 3.5" Resonated Single Midpipe Upgrade - F80 M3 | F82 / F83 M4
ARM S55 3.5" Resonated Single Midpipe Upgrade - F80 M3 | F82 / F83 M4
ARM S55 3.5" Resonated Single Midpipe Upgrade - F80 M3 | F82 / F83 M4

ARM S55 3.5" Resonated Single Midpipe Upgrade - F80 M3 | F82 / F83 M4

Regular price $825.00 Sale price $754.00
Shipping calculated at checkout.

-3 in stock

Introducing the ARM Motorsports S55 Single Midpipe Upgrade for the F8X platform, the ultimate solution for S55 enthusiasts seeking to enhance the power and sound from their S55-powered BMW. This S55 Midpipe upgrade delivers improved exhaust flow and an incredible exhaust note due to the resonated 3.5" design.  Check out the clips below to hear the ARM S55 Midpipe paired with the ARM S55 Resonated Downpipes.

- Up to +20whp / 30wtq
- Improved Exhaust Note
- 304 Stainless Steel
- Faster Turbo Spool
- Fits OEM and Aftermarket Mufflers


Crafted from 304 stainless steel, the ARM S55 Midpipe Upgrade is built to last. Its mandrel-bent tubing ensures smooth, unrestricted flow, while the lightweight design of only 17lbs reduces overall weight of the exhaust system by 15lbs. When paired with the ARM S55 Track Exhaust, you shave an incredible 40lbs off compared to the OEM exhaust system.

The ARM S55 Single Midpipe starts at the downpipe connections with a precision Y-pipe.  This allows you to connect the ARM S55 Midpipe to any downpipe upgrade that fits the OEM S55 Midpipe, including the ARM S55 Downpipes.

This section of the ARM S55 Midpipe includes a 4.5" resonator to tune the tone of the exhaust into a deeper, more desirable range, as the S55 is notorious for having a high-pitched, raspy exhaust note.  Paired with the ARM S55 Downpipes, the ARM S55 Midpipe will make your F8X one of the best sounding on the road.   

The next section of the ARM S55 Midpipe Upgrade transitions again to a Y-pipe, which allows you to reconnect your OEM muffler.  This Y-pipe connects to the single midpipe with a slip-fit connection and then utilizes the two 2.5" pipes included in the ARM S55 Midpipe Upgrade to extend to the OEM rear muffler section, or to the ARM S55 Track Exhaust.

Due to the larger size of the ARM S55 Midpipe, the OEM under-brace cannot be utilized. To address this, the ARM S55 Midpipe includes a specially designed under-brace that is specifically engineered to fit with the larger midpipe.  The under brace included in the ARM S55 Midpipe Kit is designed with  precision and manufactured from 6061 aluminum to ensure strength, durability, and a perfect fit, while keeping the weight to a minimum.  Installation of the under brace is a simple bolt-on process and mounts directly to the factory mounting points, ensuring a secure and stable fit.



• ARM S55 Midpipe
• CNC Machined Brace
• 5x Exhaust Clamps


The ARM S55 Midpipe Upgrade will fit any downpipes that connect to the OEM midpipes.

Make Model Submodel Engine
BMW F80 M3 S55 3.0L
BMW F82 M4 S55 3.0L
BMW F83 M4 S55 3.0L


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. The warranty entitles you to a replacement unit.

Please contact us via the contact page form to start a return or exchange. The return/exchange process must be started within 2 weeks of delivery, after 2 weeks we will not be able to issue a refund/exchange. A 20% restocking fee will be applied to any return once the order has been shipped. For any questions regarding returns or exchanges feel free to contact us at or reach out to us via the contact form and we would be happy to help.

You can find additional details on our return and exchange policy here.




Horizon Motorsport has one goal: to make our clients happy. We aim to provide the highest level of customer service and the highest caliber parts, all at the most competitive prices. Have a question or concern about a product we sell? Send us an email at


Orders typically ship in 1-2 business days from our location in Los Angeles, CA. Transit time usually ranges from 3-5 business days, depending on where you are located. We offer worldwide shipping, if you need live outside of North America, shoot us an email and we would be happy to give you a quote!

Creating life-long customers.

As a small business we pride ourselves on creating long lasting relationships with our customers who know that they can count on us for any of their BMW needs. At Horizon Motorsport our mission is to provide a unparalleled customer experience to keep our customers coming back.

A Company Owned By Fellow Enthusiasts.

Horizon Motorsport was founded in 2019 in Los Angeles, CA by fellow BMW enthusiasts. We have experience with nearly all makes and models and have been actively involved in the Southern California BMW scene for over 3 years. Our unique insight and experience with the BMW community and other high end European-oriented brands gives us the knowledge and ability to stock only the highest quality parts from the highest quality brands.