Maad Maxx - F8X BMW M3 & M4 Rear Exhaust Section - 3 Can Valved

Active Autowerke SKU: ExhF8XM-REAR-G3

$ 2,499.00

Only 5 left!

The Ultimate F8X BMW M3 & M4 Rear Exhaust System - now with valves

At Active Autowerke, it's not ONLY about making as much power as possible. For over 30 years, power has been the end result of improved performance due to our relentless desire to develop a refined, quality product. This philosophy behind our performance parts is best represented by one of the newest additions to our F80 BMW M3 and F82 BMW M4 collection.

The Active Autowerke F8X rear exhaust was carefully engineered to eliminate the unflattering sound of the factory M3 and M4 exhaust, while also allowing for optimum flow and resonance. Every effort was made in addressing the not so appeasing sound of the stock OEM exhaust, but in designing an exhaust worthy for an "M" car. We believe our rear exhaust combined with our mid-pipe offers the deepest sound and best performance of any other system on the market today. Available for both models, this axle-back exhaust gives your BMW the deep, throaty, growl a car of its caliber should have had from the factory! And NOW, after many requests from our dedicated customers, we are introducing a valved version of the ultimate exhaust which has been dubbed "Maad Maxx" by our team. We will update dyno charts later but this exhaust flows even better with its valved system.

See what actual customers are saying on BimmerPost!

***Before your order ships you MUST sign and return the Off Road Use Only Waiver available HERE. Please email, fax or take a photo of the completed form. You can email it to your sales rep or to and you can fax it to us at (305) 253-8921***

Key features

  • Made in the USA
  • 18+ WHP gain over stock*
  • 30+ LB-FT gain over stock*
  • Quicker turbo spool
  • Low, Deep Rumble
  • Flex joints to reduce vibration
  • Double-canned muffler to reduce resonance
  • Each exhaust test-fit on our F8X Exhaust Fixture
  • Guaranteed to fit all F80 BMW M3/F82 BMW M4
  • Includes all necessary installation hardware

*When paired with Active Autowerke F8X Mid-Pipe

Mustang Dyno Results:


  • Active Autowerke F8x Mid-Pipe
  • Active Autowerke F8X Rear Exhaust Section


RED Line Stock Figures: 380 WHP | 371 WTQ

BLUE Line Full Active Autowerke Exhaust: 398 WHP | 401 WTQ

GOLD Line Full Active Autowerke Exhaust Run 2: 397 WHP | 398 WTQ

Note: Active Autowerke Full Exhaust System is recommended for, BUT NOT LIMITED TO, off-road or racing applications.

Refinement Meets Performance:

The OEM F8X exhaust utilizes the services of middle and rear silencer as well a pair of exhaust valves. It is supposed to be a freely-flowing exhaust that produces an external sound that meets the demands of a M3 or M4.

The middle silencer has a small crossover that allows for noise dampening while the rear silencer (muffler) has a reflection chamber on either end that re-directs exhaust gases to the opposite side they entered from (drive's side exhaust exits on passenger side). When the exhaust valves are closed, this helps eliminate the back pressure buildup that occurs during noise dampening.

After analyzing the factory exhaust, we realized less would be more in regards to our F8X exhaust.

We began with a complete redesign of the mid-pipes. This involved drastically increasing exhaust flow as well as reducing the uneven, out-of-sync turbocharger's sound that many F8X owners have complained about on the forums. We were able to achieve this on our F8X Mid-Pipe (sold separately) by using a single pipe that not only cancels out the offensive sound, but allows unrestricted exhaust flow.

The most noticeable difference between the Active Autowerke F8X Rear Exhaust Section and the BMW factory exhaust is how we utilized the muffler. Our design incorporates two mufflers that create a huge resonance chamber to further cancel out the weed eater noise.

This design also allows exhaust gases to crossover freely without being forced in a certain direction - eliminating back pressure without sacrificing that deep, aggressive rumble that some turbocharged cars are known for.

Note: Active Autowerke GUARANTEES that each and every F8X Rear Exhaust Section will be a precise fit. Every Active Autowerke F8X Rear Exhaust Section is test-fitted on our in-house F8X Exhaust Fixture as part of our quality control measures.

BMW M4 installation instructions