Thanks, already read that...mt X5 is 2001,/w NAV, no DSP. The dealer couldn't find that part number too. The guy there wasn't very educated, but he said he doesn't see DSP nowhere on his screen. I checked on the display and couldn't find any equalizers or DSP settings or anything like that.
SO, I assume I don't have DSP.
I did some research today and found this
http://www.shophabberstad.com/bmw-61-12-8-386-398.html
Looks like the one I need and I ordered it.
Did I do the right thing?