Kinda confused...

I'm looking for 18" wheels for a 2006 GP.

Tirerack recommend 235/50-18 for either a 7.5" or a 8" rim.
Superbuytires recommend 235/40-18 for a 7.5" rim.

Both tire sizes I don't like.

Can I do a 245/45-18 on a 7.5" or 8" rim?

If you go with 18", what tire size do you drive?