i think that stands for 200 watts seriously though...yes cheaper amps can introduce noise problems more often. after you make sure your grouds are good, try running another rca outside of the car just to test it... if you still got noise, most likely the amp. very slim chance it would be rca output off the deck. and, i would never put a ground loop isolator/noise filter in my car to get rid of engine noise (at least on main rca's to the amps). i would get a new amp before i did that. just my .02