Holy $#!$ that was an expensive amp. I think the audio guy meant it does not have RCA cables, it uses balanced cables which are much better but rare in car audio. You could replace with a different amp but you'd have to run different cables. And get an amp that duplicates the functionality.
If this isn't the same model it might be similar enough:
http://www.woofersetc.com/p-10299-re...amplifier.html
The bad thing about a previous owner doing all that is it will cost you a lot to change it in any way....
One thing to think about is getting the amp repaired. Zapco amps are built very well and should be repairable. Contact them.
~Will
2004 Imola Red 330i
6MT, Black Leather, Silver Cube, Cold Weather pkg, mostly Stock