It's a MC120 by Soundstream ( http://www.soundstream.com ). Though the MC120 isn't listed as it is about 8 years old.

So, you think the Amp is making the distortion in the MTX 6X9's in the rear deck? Will the amp cause distortion?

The stock front speakers actually sound better than the MTX 6X9's. The aren't distorting near as much. I'm hesitant to get rid of the speakers that ARE sounding good!