question for you audio heads out there. im wanting to add subs to my hhr in the lil' cargo trunk in the back of the hhr. but this is where the fun begins i want to be able to put two subs and the amp in it and still be able to close the lid to hide them (for protection if hauling things) so was wanting some suggestions on what you think will fit the deminsions and brand of subs and amp and how much wattage i should to push the subs with. thanks for the help

 

Check out the "various sub installs" thread, some similar ones in there.
However if you need to hide two subs and an amp, you will probably have to ditch the spare tire.
Personally, I would go with a single 10" and an amp small enough to fit beside the spare tire, mounted on side opposite the battery.

 

I want to do the same thing and have been doing some light research on flat piston subs. Look around the web for those and you'll get a start.

 

I've got two 12's and amp over my spare tire. Only lost 2 3/4 inch of floor height. Everything is flush mounted with a vinyl trim around subs and amp. Also a grilled panel over that for protection. Its posted in the install section.