Is it possible to replace the Shaker 500 headunit with an aftermarket headunit(I'm thinking Pioneer DEH-P9800BT) without doing major surgery? I have an 06 GT coupe, and have been to several local car stereo places. They all seemed to think it would be a bad idea, and would be very expensive. One guy even said you'd have to bypass the amp, lose the midrange, and would have to rip out the factory speakers. Does this make any sense? Thanks.