good afternoon everyone. new to this and just bought my 07 hhr. I installed my head unit and now wanna install my amps. whats the best way because im not use to the battery in the trunk? Will I need a bigger battery??

 

Should be able to use a GMOS-LAN-03 and be fine.


My 1LT which says it had Onstar (even though I don't have the rear view mirror for it) and no XM I used the GMOS-LAN-03. Was able to retain factory chimes, and used the AWSC-1 to retain my steering wheel controls.

 

I moved this to a new post, from an old 2008 thread.
Welcome to the site!
You will have to determine the voltage and ampere needs of the amps, some have added a second deep cycle battery

 

Modest amps up to 1000w RMS aren't a problem for the original battery, ive been running that for years.
I think the best way is to mount amps in the rear, more space and less run for thick power wires.