^^^I agree. I've been experiencing much better throttle response since I installed it. But I think it's because my old stock catback was so old that it became more restrictive. If anything, it may have simply brought back the performance that was originally there when the car was a little younger. But I guess people often confuse that and think they actually got a performance boost. The M3 catback definitely wasn't designed for the 325, in fact it may too free flowing. It's probably better suited for the 328 as a mod. But it was the choice I made, rather than pay more bucks for an OEM replacement.