i currently have 20 x 8.5 rims w/245/40/20 tires w/20mm offset. they are way too low profile for my RX 330 and make it seem smaller than with the 18s (because of the tires). can i go 255/55/20 w/o it rubbing? or even 255/50/20? any recommendations would be very helpful as i am unable to return the rims and actually do like them, just not the tires.

 

That is almost the size tire most of us put on your GS's with 20's. I don't know what size tire would be best, but I would definitely suggest getting a tire with larger sidewalls as a 50 or 55 series tire.

 

Agreed!