ChuckW

I just had a new stereo (pioneer) installed in my 1999 EX300 due to the factory CD changer going out. Once I got the stereo installed by the place I bought it from, I noticed this sound in the background that won't ever stop. They told me it was because of the amp in the car and that the only way to get rid of it is to rewire the speakers bi-passing the amp. They want to charge me $120 to do this. Does anyone know if this is true? I think they might be trying to wrip me off. Also, is it easy to rewire it myself, or change the amp? Where would I get directions on that? I can't find it here. THANKS!!!!!!