2002 tahoe subwoofer

You will need a relocation harness for the 2002 Tahoe in order to retain all the OEM functions .The removal of the factory radio in these vehicles will result in the loss of the door chimes and other vehicle systems that rely on the OEM radio. There is also the possibilty of the airbags inadvertently being disabled.

You can contact Best Kits for additional harness that you can get to help you with your installation: http://bestkits.com/bk_contact_us.htm

Why would you want to downgrade to an aftermarket radio, just to get good sound?

I'm pretty sure that the factory amp is found behind the left rear panel, where the subwoofer is.  Most of the wires should be just the standard GM colors.  The subwoofer part shouldn't be too hard to figure out, since it's right in the same area anyway.

Attach a nice line-out converter after the factory amp, add your own more powerful amps, a larger subwoofer, and maybe some better speakers, and you should be all set.