Grail exhaust system for BMW M4 (F82/F83)

GRAIL exhaust system for BMW M4 with selectable tailpipes in stainless steel or black 

• Loud but Legal

  GRAIL valve exhaust systems with ECE type approval can be used on your EU vehicle without registration. They are made of high-quality L304 stainless steel, handcrafted in Germany, it produces a distinctive sound that will give you goosebumps the first time you start your engine.
  If you are driving an imported vehicle with a vehicle registration certificate, please check before purchasing whether you need to have the exhaust system registered in your vehicle documents.
  

  Loud – maximum volume

  You ride your GRAIL loud but legally.

  With the intelligent control you get the legal maximum out of your engine sound.

  The use of highly effective silencers allows for maximum volume and wonderful engine sound outside of the test areas, because only in these areas are the flaps of your GRAIL closed and only when closed is the rear silencer part of the exhaust flow.

  This is how we achieve pure engine sound and maximum volume.

  Your GRAIL can also be quiet.

  With a GRAIL you get two vehicles in one.

  We use custom-developed mufflers, which are developed and customized for your vehicle in the GRAIL sound lab. The combination with solid flaps is designed not only for maximum sound output when the flaps are open, but also for maximum damping when the flaps are closed.

  If you drive your vehicle within the respective test ranges, your GRAIL will be no louder than the stock system. Using the highest quality and materials, we achieve the unmistakable delta between loud and quiet that has been unparalleled for years.
  

  Flow

  Your GRAIL has been engineered to minimize exhaust flow interference. A significant improvement over the stock system is evident in the larger pipe diameter and reduced taper. Your GRAIL doesn't interfere with the exhaust.
  

  Massive

  Our stainless steel flaps made of CNC-milled solid material switch within the prescribed measuring ranges depending on the model and thus allow the perfect combination of backpressure reduction and extreme volume of pure engine sound.
  

  Quality Made in Germany

  With a GRAIL, you get what you've always been looking for: the highest quality workmanship, the best materials combined with the maximum possible sound for your vehicle.

All brands, model names and manufacturers mentioned in this shop such as AUDI, BMW, Hyundai, Kia, Toyota, VW, Tesla are used solely to describe the compatibility of our products . They have no connection with the respective brand owners and, unless expressly stated, they are not original parts from these manufacturers.

FLOW DOWN® is an independent supplier of tuning and accessories. The use of the brand names mentioned is for guidance only and does not constitute a collaboration, licensing or approval by the respective rights holders . All trademark and name rights are held by their respective owners.