I got a set of 4 15" Audi Alloy (15x7, ET-45) and I plan to purchase
a set of tires for these rims soon. Please advise what size of tires
I should consider. I understand I need 1/2" spacer and longer lug
bolts for the front. I may need longer wheel studs even if I don't
use spacer for the rear. I already got 10 longer audi lug bolts
and 10 longer Porsche studs. So there is no need to get into that
again, unless someone else wants too. I think VW stock is 14x7 ET-30.
I should use 15mm spacers for the front but 1/2" should be close
enough. My 83 westy is a 2WD.

Let's deviate from tires and talk about your wheels.
The original Vanagon wheels are bolt-centric.
The Audi wheels are hub-centric.

Has anybody experienced out-of-round conditions (vibrations) with Audi
wheels installed on their Vanagon?