Looking for GM or Hummer tech in Vancouver area.

[finall]

I just got a nasty $3K bill for replacing the cat assembly by the local GM dealer.

That is after 2 other local GM dealers failed to diagnose the problem with our H2, first one claiming it was plugs, then wires.
The 2nd dealer said it was heads.
I had to figure it out myself, but then got a huge bill from the 3rd dealer who actually completed my requested cat replacement + 2 damaged 02 sensors associated with the passenger side plugged cat.

Can anyone help me find an independent repair shop in my are who does not charge the outrageous $135-$160 per hour labor?
Someone who has GM truck or Hummer experience and actually knows hot to diagnose and fix GM trucks or Hummer vehicles?

I am in the Vancouver BC area (lower mainland). That is SW British Columbia, Canada.

Would very much appreciate it. Thanks.

Need to service the air ride now, and dealer is asking for $2500++ parts and $$$ labor to repair it.
They are telling me to replace the entire air ride pump assembly vs just repairing whatever part is actually faulty.
So that is another $3K. Not prepared to dish that out.

Addendum: Tonight sprayed soap everywhere and found a leak in the passenger side airbag. Seems to be the only leak area and once I replace it I will know whether that was the only issue. Certainly a cheaper fix.