Hummer of Union City did my install and they did a great job.
Jim Tworek, ASE Master Certified Service Technician did the work. His contact info:
(770) 306-6000
jimathummer@yahoo.com
I haven't been back to the dealer since the install, so I can't say that he is still there.
I doubt you'll get that kind of install price, however (I paid full MSRP for my H2 in late 2002 at this dealership). Also, keep in mind your GM warranty is pretty much toast, even if a dealer does the install.
Let us know how it goes!