Anyone have any suggestions on aftermarket amplifier/subwoofer installation? Had one installed at local, reputable, high-line car stereo shop and they can't seem to get it right after several tries. System volume is very irratic. Help.....

 

hey dont know if this will help but i know that all mercedes have something that automatically ajust the volume for higher and lower rpms for u automatically, its probably the most retarded thing that they have put into their cars but that might be it.