After messing with the stereo levels I wasn’t at all impressed with the level. I had the audio set at maximum of 35 and the sound was just average, though it wasn’t distorted.

Today I rewired the inputs by taking the RCA plugs and separating the positive and negative into discreet wiring to the aftermarket plug I purchased. The quality was much better and the annoying popping sound was gone when changing  in the radio panel. Since I was doing a rewire  went ahead and wired the car for a rear trunk sub woofer which meant fishing wire throughout  small confines and the precise trim fitting of a Mercedes Benz.

Since the trunk space is limited I had to use a small 12″ kicker subwoofer fitted into a small enclosure that the available space allowed. The amplifier is also a small footprint model made by Alpine. It is only a 500W model but that should be enough to at least indicate if I need to upgrade the equipment.