I'd wonder if installing your own tow system would void your warranty on the HHR. At the least, putting in the wiring could fry the computer, which is very expensive to replace if the warranty is voided.
That vented, I also wired and set up for towing my Rubicon. It is possible to do one's self. But... the warranty issue raises it's ugly head.
07 TM 40D;ISL 450 Cummins(upgraded). Very happy w/coach
Gnarly toad to scoot around.
Geocaching, hiking, fishing, National Parks, Civil War sites.