Sub Options

I'm looking into adding subs/amp where do they fit nice?

H1, H2, or H3 ?

Under the back seat!

if youve got an h3 with the monsoon woofer-jl audio makes nice replacement that fits in the factory location-if you dont have the monsoon woofer, you can still get the jl, but you'll need to pick up the factory trim piece to cover it
http://mobile.jlaudio.com/products_stealthbox_make.php?make_id=90&model_id=826
 

It's an H3 with no monsoon I have installed a Valor 660w head unit and JBL speakers in the doors........I like the JL audio box but what does GM want for the cover???
 
I'm headed to my distributer now to look at JBL amps and subs !!!