Audio Systems: Scratchy noice from new car stereo, ford escort lx, pioneer mosfet 50wx4

Question
My fiance just had Best Buy install the Pioneer MOSFET 50wx4 Cd player they took out of her brother's car when he bought his new system. She has a '93 Ford Escort LX, and was very disappointed with the fact that there is severe static/distortion when she turns it up past 10 (which is not loud at all). I'm guessing it might be, since it is replacing the factory radio, that the speakers can't take the watts, but I thought 50 watts was pretty standard. We're going to take it back tomorrow, but it would be nice to be somewhat informed before they try to sell us speakers to fix the issue. Thanks

Answer
Paul,

 ok .. best buy = big mistake .. you are alot better taking your car for an install to a private more grounded shop something local because they are normally alot more skilled on installing unlike best buy , circuit city ect.. but no need to fear i will see if i cant get you up to par about what to look for .. now i will start off with the wattage problem it can be the cheaper factory speakers in the escort factory speakers cost on average 3 dollars to make and most cant handle over 15-25 watts RMS so the 50x4 which equals to normally a little over 40 watts RMS per channel can really hammer the under-par speakers .. plus if you have bass/treble turned up this can also cause the distortion ... now lets put the fact of equipment aside another thing that could be wrong is they didnt insulate the wires good and get good connections * but doesnt normally cause so much interferrence* you can narrow down the problem by installing a noise eliminator / distortion blocker that should take care of the fuzzy static but if it doesnt its a problem in the head unit or the fact of overpowering the stock speakers... now normally i would say drive down and bitch slap the guy at best buy but not in this case i think in my own opinion it will be the speakers or un-tuned bass/treble or loud features.. but dont quote me on that that is just the more common assumption from my experience.. i hope i have helped you out if you need anything else let me know

thanks