My car has a "Bavaria C professional RDS", it came with a head unit, a 6 Selektion CD Changer and an AMP/Radio Receiver unit at the right side of the trunk. Yes, if I remove the stock amp, I'm removing together the radio receiver.

Regarding some post about silent speakers, I spend some time with some trouble on my driver door twitter, it was going in and out depending on the road bumps. I finally notice that the problem was inside the stock AMP. There was a board inside it, plugging at 90 degrees in the mother board of the AMP, that got one pin having trouble in its connection, so I decided to solder it, only a couple of them pins looking weak. Anyone will notice the type of connection is easy to solder. The problem was vanished up to now.