My late best friend had several Mach460 cars and he and I put aftermarket speakers in all of them. The Mach460's are not bad, they are low powered, but not bad. If you just want different speakers, make sure they are the same impedance as the Mach460 speakers and have a high sensitivity rating/lower power rating and you can use the factory amplifiers. The best/better/safest/smartest way is to remove ALL of the Mach460 components, amps, speakers and use aftermarket amps and speakers. Takes more money and time, but worth it. We never used the factory Mach460 amplifiers because the impedance's are weird. You can use the inputs from the amps to send signals to aftermarket amps. Fiddling around with the Mach460 components is a pain though. Strip it, replace with aftermarket and pat yourself on the back.