I used to have bluetooth interference issue about MPE. The valves may randomly close after they are opened. I talked this issue with several dealership and get negative feedback. And I talked this issue with other owners who had this issue, no one can really find the reason.
Finally, I determined to take MPE off and find a new exhaust instead.
Then I did almost 3 months research, analyzed the personality between
Akrapovic, Fi exhaust and Amytrix (top 3 for M2 so far)
Akrapovic:
Tone: similar to MPE
Loudness：a little bit louder than MPE
Controlled by Bluetooth (Might have interference issue, not suggested go with BT, you can choose Akra without BT)
Pops and crackles: it has a lot pops and crackles, but not loud enough
Turbo back sound when release the throttle: similar to MPE
Fi exhaust:
Tone: much more aggressive than MPE
Loudness: way louder than MPE, especially in tunnel.(MPE in tunnel is not loud at all)
Controlled by just remote controller(Not bluetooth, Bt is an option, not necessary)(No interference issue so far)
Pops and crackles: many pops and crackles, loud enough
Turbo back sound when release the throttle: waywaywaywayway louder than mpe, very attractive and addictive.
Amytrix:
Amytrix is loud enough but not attractive.
It has the high tone but definitely less pops and crackles
Controlled by just remote controller(BT is an option, not necessary)
I drove MPE for 4 months and Fi exhaust for 3 weeks. So far I honestly love Fi exhaust so much.
my purchase combo is Fi full exhaust with catless, without BT module.
I dont have time to post pics and videos about my Fi exhaust, but will do in next couple of days.
here's some videos which I watched during the research, hope these help:
See you guys later.