Wheel and tire size?

[Comfortzone]

I plan on putting 20" rims and low-profile tires on my XLR. What is the largest I can go in front and back without rubbing?

I had 20" Pasati wheels on my last XLR, but the store that sold them to me went out of business. What I had on it was wider in the back, but without their help I do not remember the exact size.

Can anybody advise based on their vehicle or others XLRs you know?

 

[Comfortzone]

I am sure I posted wheel size on this forum, but I cannot remember any of my old login info to see old posts.