The "upgraded" HK system in my '98 Z3 accepts speaker-inputs. It's a leased car so I do not want to replace the amp and speakers. Right now the Empeg is going straight into the amp, and I guess due to the 4V pre-outs I am actually getting good sound, just not enough volume. Anyone know of a good trick to boost the power up a bit? I was hoping I could find a cheapo little amp that I could shove behind the dash that would give me just enough juice to drive the factory amp where it should be. I don't believe there is a way to bypass the line level converter in the factory amp.