Courtesy of Silver Systems (Powerflow agent) in Leek, Staffordshire:

Step 1 - cut off rear silencers:


Step 2 - discard rear silencers (and save about 20kg!):


Step 3 - leave everything forward of this well alone:


Step 5 - weld on stainless steel 3" pipe in its place:


Step 6 - use 3" oval dual tips for that stock Alpina look:


Step 7 - sit back and enjoy the sound:


Will try and get a video of the noise up but it sounds like a NASCAR! Bit of a boom at 1900rpm under load (and a lovely deep burble at idle) but the sound is so clean above 3000rpm is glorious.

Odd as it sounds (and I might be over-sensitive here) but it feels like its lost a bit of that second kick at about 5000rpm that it used to have, feels more linear through the rev range but a bit down on power?

 

Can't wait for the vid! Well done! These cars are too silent when you get on them.

I guess if you had done a before/after dyno, you could confirm your butt dyno is right or not...

 

My link

 

Holy crap that sounds awesome!!! Listened to it a few times!

Link for the lazy:

http://www.youtube.com/watch?v=gO-rFUbcdE4