[MR.]

Before you are asking why the stickers? I am driving a road rally the next week with Shmee150 and our starting point is in Ljubljana, Slovenia. The tour brings us across the balkan to Italy and France. The stickers will come off in 8 days or so.

Now let's discuss the exhaust system as a whole. Interestingly, the system is a lot louder on the outside, but not a lot louder on the inside. Inside the interior, the sounds levels (also because I disengaged ASD) are slightly louder than stock. You hear a higher soundtrack pitch coming from the exhaust and there is a lot more burbling. You can clearly hear the influence of the new set up, but it is never annoying or droning which is what I had hoped for.

The cold start up is a lot louder, as expected. The exhaust follows the ECU modes and the modes available via the Sport and Traction button. The sound track of each of these modes is of course louder and especially the 'hidden' exhaust mode via the Traction mode has turned some notches up!

Video: before and after!

Listening to the sound track, it is a lot more raw, and feels quite common to the set up available for the BMW M4. More raw, lower in tone, more burbles, more volume, never droning or annoying. A clear difference between stock and Akrapovic is noticeable by ear, but as stated above this is mainly the case outside and not inside.

Another noticeable point is the fact that you really clearly hear the woosh sound from the turbo after lift off. It is way more noticeable than before and it is a nice extra to the exhaust set up.

Overall, it feels like a really thoroughly engineered set up both on sound (inside/outside) and build quality. You really feel like it has some decent engineering all across the board. The materials are wonderful and the sound is exactly what you expect without it being annoying. All in all exactly the set up that Akrapovic wants to achieve with their systems.

Early next year I will install the catless downpipe and make a comparison for you guys, so that you know how loud that is. For now feel free to ask any questions or let me know what you think of it. I will try to reply and answer much as I can.

MR