another two cents worth of mine , for some odd reason , on all my cars including the Ms , i have noticed that changing the center of the exhaust system is a must whislt keeping the stock original rears in place , seems to give the best performance , coupled with a nice induction.
on my E36 M for eg. , just to give you a indication , i had on a RGM exhaust system worth 10k or something , on the rollers it made the power , some odd 173kw ATW , but on the road it was a dud , i changed back to the above system as described in the begging of this thread and the car is running mad , and i have tested against other Ms ,on the road, supporting some very good mods , believe it or not , just the center exhaust change on the M and it is in front of the modded Ms
but ja different strokes for different folks.
:thumbsup: