I got my car from Suburban in Farmington Hills....
Do I recommend buying from Suburban in Farmington Hills? Not really. They were just able to get me the exact car I wanted at the price of Fox VW (which wouldn't of been the "exact" car I wanted)
Service department at Suburban in Farmington Hills has taken good care of me though (with my mods on my old car, 2009 GTI)
As for Thayer....they sell for invoice too if you're a member of MIVE (they're a sponsor on MIVE -- Michigan VW site).
I just don't know how it works when ordering a car though.
They have discounts on VW Parts thru MIVE, so that's where I get all my parts (discounted).
Go with Thayer!
Any more questions...let me know!