If the beetle with good chassis weighs 800-900, including heavier engines and transaxles, most wider 17 and 18" tire sizes are more than enough, maybe.
What is too much? I'v seen on some beetles 215-235/40 tires at front and 245-265/35 at back, and i have considered 215/40R18 at front and 255/35R18 at back. Allthough 225/40R18 is much more common.
How is to drive with 17 or 18" wheels and different tire sizes on at front and back?
I have been looking hollowspoke 993 turbo 18" wheels and speedline lookalike kerscher KRS wheels, which are not the heaviest wheels. And i would prefer 7,5 front and 9" rear.