Hi guys,

I was directed here by some guys over at ZPOST, who claim you guys are pretty much the foremost experts on BMW audio systems, so here's my question.

I have an '03 Z4 with the Top-HiFi system (10 speakers, DSP). Amp has the high tweeter cut out on the right hand side above a certain (not very loud) volume, which was annoying enough I replaced the amp with a newer one I found online at another BMW forum. I pored over the RealOEM database, and according to them, the amp I got now is a 'newer' version of the one I replaced. Both part numbers are listed for Top-HiFi for my particular model car.

Old Amp: 65.126932417
New Amp: 65.126946727

Now, I replaced the old amp with the new amp, and turned the radio on. Audio works, no more cutting out on the right channel, but my head unit no longer has a menu option for DSP, and the bass sounds weak compared to the old amp. I think the new one I got is from an X3, as the part numbers match.

I've read that sometimes you have to have the amp (?) recoded to match the car, especially when it's from a different model, would that possibly be the case here? If so, is this something I can do myself somehow?

Thanks for any suggestions, as for now I'm considering going back to old amp and at least have some not very loud decent audio.