1. Does it void the BMW warranty?
Let's face it: it's no official BMW approved part, so the answer risks to be affirmative. However, BMW mounted it in 2011 on the MotoGP Safety Car 1M, so the quality can't be that bad after all (by the way, Akrapovič is an official partner of Audi Sport for the endurance race series and since 2012 also of BMW Motorsport in the DTM Championship - so we may reasonably assume that, in general, BMW appreciates the Akra technology). In the event of car trouble, it remains to be determined whether a caus(ation)al link effectively exists between the Akra and the trouble.
2. I'm thinking about getting the evolution system with wireless kit, but not the downpipes, do they make a big difference?
No personal experiences with the Evolution System. Got the modest "N55 + Akra Slip-On axle-back exhaust + wireless kit" setup (to each his own, but to my ears that setup strikes the right balance); though, I do know that catless DPs = noise, smell and requires coding; you will not regret getting the wireless remote:
bi-polar exhaust (dis)order (valve closed for the Dr. Jekyll times and valve opened for some Mr. Hyde hooliganism fun).
3. With the valves closed how similar is the sound compared with the stock sound? (With the valves open I know it is just brutal)
Similar to stock sound, but in a different way (a little more refined ?). With valve closed, no fumes exiting the outer pipes (so during the first minutes, those queuing behind you in traffic may think that those outer pipes are fake - but then again, same goes for the outer pipes of the Ferrari Enzo on start-up and below a certain rpm range
).
4. Did anybody already have any problem because of the exhaust itself? or anything related with it?
As regards the way it operates, I neither heard nor read negative testimonials. As regards mechanics or aesthetics, there was initially an issue with a rubber mounting, but that was resolved by Akra (
http://www.1addicts.com/forums/showp...3&postcount=64) and some owners experience a slight different spacing between the tailpipes (but that could be related to the way of mounting/orienting the tailpipes) (
http://www.1addicts.com/forums/showp...0&postcount=27).
5. I read that when you get the exhaust you have to make some changes in the ECU, it this true?
As long as you leave the stock 1M downpipes sit where they are (no replacement by catless DPs), normally no codes will be thrown at you (no coding required - the sensors are located inside the DPs, not inside the midpipe or inside the axle-back exhaust).
6. Does it affect the fuel consumption?
Yes, but as a self-inflicting side-effect: for aural pleasure reasons you tend to stay more and longer inside the rev band ranging between 3000rpm and 5500rpm (oil temp might climb a little and fuel range might drop a little); other side-effects: less music playing through the speakers and windows are regularly opened a little.
7. The wireless kit has any batteries? What if it runs out of it? Easy to change?
The wireless remote has a battery, but forget about it or about changing it (if the battery lasts more than half a year, call yourself lucky
); actually, the wireless plug belongs inside one of the 12V sockets (cigarette lighter socket or the socket between the front seats), not inside your pocket; except if your 12V sockets are occupied by other electronic devices, a battery is definitely redundant: if you keep the wireless remote plugged in, it's permanently operational, ready for toggling between white mode and red mode (
aka "Thunder Mode").
Have a look at the little list of 10 'features' experienced so far with the N55 + Akra setup:
http://www.1addicts.com/forums/showp...8&postcount=36
Cigarette lighter 12V socket (EURO spec 1M):
MotoGP Safety Car 1M cargo at El Prat airport (Barcelona) on route for the first MotoGP of 2011 (March 2011):
