[Forklift]

if you wanted to keep the stock radio and have it directly control the XM , you'd have to go to GM for the XM box and ant and its around $800 from what Ive heard from my customers. If you wanna add your amps just add a hi level/lo level rca adaptor and tap off the windsheild wiper fuse cuz it goes on/off at the same time as the radio.

 

[carterbeauford]

for $800 you could replace the whole thing with a nice alpine headunit and XM tuner. this would be much better for running your subs. but if you want to go the cheap route you can get a delphi XM roady for like $125 and use a line output converter for your amps.