Did you not see my Dyno results? I had M50 Inlet, BBTB and BBTCB (Yes it had TC rather than LSD) with DaveF induction. It made 20BHP and better torque curve buts its not noticeable...
Ummm, I had one and it was extremely noticable, like an extra 1500 useful revs, I also know at least 10 people who would agree - the engine is artificially stangled at high revs, how can freeing it up not be an improvement?
I wouldnt even drive one without it having been done first. Seriously.
Yea it's good results according to the dyno run, but I didnt notice it driving the car. And if Alpina527 still manufactures the kits to bolt straight on it is worth doing!
And just to throw a spanner in the works, you could just save up a few extra pennys and buy a cheap M3, problem solved