[HDEddie1]

Like others who wished for a little more sound from their F10 550i, I was ready for a change but not yet ready to spend big $ for a full factory M5 system or the same amount for the high end aftermarket systems. So, thought I’d try the M6 muffler mod done already done by others. I knew from previous posters that it wasn’t a bolt on. But its really not too tough for any good muffler shop.

Once I got my hands on a used set of M6 mufflers, the biggest challenge for the muffler guy was lining up the twin exit points on the M6 muffler with the new tips. The old ones don’t really work because they’re significantly longer and point inboard. This will be a challenge even if one were to upgrade the rear facia to an M5 style or any other aftermarket facia. Nevertheless, any good muffler shop can shape some stubby twin exit pipes onto the M6 muffler for you to slide any tip finisher you have in mind.

The next challenge is the pipe transition. The M6 muffler lines up with the original 550i post axle pipe reasonable close but a reducer sleeve will have to be fabricated since the M6 muffler has a 2 1/2” inlet vs the 550i’s 2 3/4”. Some sharp exhaust guys might say that the downsize in pipe will result in power loss but I think it is negligible if even discernable since BMW inadvertently crushed and kinked the F10 factory 2 3/4” mandrel shaped exhaust pipes in enough places to pretty well negate maximum exhaust performance. And after all, if the rest of the exhaust system remains stock, then this minor downsize at this point is even more negligible, IMO.

The last challenge is the muffler hangers since none of the M6 hanger bracket points match the F10 chassis. Again, no big deal for any good muffler shop. They just cut off the old hangers on the muffler (or leave on) and fabricate some new hangers from rod stock to match up with the mounting points. Not as nice looking as the factory hangers but the work just the same. The finished muffler will hang about 1” lower than the stock muffler but you can hardly notice it.

Once done, the big surprise is the sound. Not totally unfamiliar with sports muffler sound on factory stock cars like AMG63 and Audi S4, I was hoping for something close. Well, these M6 mufflers do not disappoint. On cold start up and off idle part throtlle, the mufflers are heard. On WOT from a stop, these muffler are heard! NO, they don’t sound as loud and raw like the high end systems with their full mandrel bent pipes, X pipes, and resonator delete, but no question...these M6 muffler do make their presence known.

At steady cruise, the muffler are barely noticable. At part throttle or any small throttle change (making turns, changing lanes, the mufflers drone a bit (more like a BRRRRRROOM sound) between 1500-2500.

And that is the problem, at least for me. Its too loud sometimes and quiet at other times. I just didn’t notice this with the AMG nor the S4 that I have driven. This could be the the Merc is a non turbo engine and has a different firing order (and bigger displacement) and the S4 is a blown 6 with a likewise different firing order. I’ve not heard F10 posters who have done the M6 muffler mod to their 535i complain of this variance in sound nor the drone/broom sound at low speeds...perhaps its peculiar to the N63 V8. Or, maybe I’m just getting too old.

The “too loud” for me is at off idle and slow speeds. The car sounds off (!!!) and attracts attention. It seems to attract the young guys with in other souped up cars to take notice and maybe want to street race you. I’m too old for that (lol).

I’m back from a 600mile road trip visiting buddies who are car guys. One has a souped up NSX and the other a vintage Chevy V8 on headers. Both absolutely love my M6 muffler mod and said that it sounded “great” and could be even louder. Neither of them had or know much about BMW cars, so what do they know (lol).

So, here's a quick picture log:
-First pic shows the transition pipe from the 550i exhaust to the M6 muffler inlet. The twin stubs added to M6 muffler exit and 3 1/2” tip finishers slid on.
-Next pic shows the M6 muffler mod done with quad tips, staggered and 1/2" from rear facia.
-Last Pic shows the M6 muffler mod post mortem...just removed from my F10.

Sorry I can't post video/sound clip but trust me...it DOES sounds like the other posters M6 mod sound clips (only louder in person).

Final Thoughts: M6 muffler mod DOES FIT. It is cheap, loud, and fun. But, NOT as nice as a full factory tuned system (stock F10 M5 system) or high end tuned system.

Note to self: I’m getting too old for this, so its back to the stock F10 system, listening to cabin music, and enjoying the quiet ride.