My wife is planning on upgrading her stock 02 wrx rims to an 18". She really likes the "dish" look, but we are kind of lost as to what exact size would give the best "dish" look, and fill in the fender gap well. She will also be upgrading the suspension to Tein Flex, so it will be lowered. What is the largest 18" (18x7.5, 18x8, or 18x8.5) rim that will fit under those catagories. And, what would be the optimal tire size for each rim size. Please include the proper offset, and why the offset should be that way.

P.S.- Am I correct in my understanding...that the lower the offset, the more of a "dish" you will get?

 

The "dish" look has more to do with wheel spoke geometry than offset. It is indeed easier for a company to make a wheel with a "dish" look with lower offset, but the two features (offset, dish) don't always correspond directly. Assuming this is a WRX sedan, the wheel size should be 18x7, 7.5, or 8 with offset ranging from 48 - 52mm. The tires should be 215/40-18 or 225/40-18.

For best flexibility with the coilovers and camber adjustments, I'd recommend the narrower of your wheel choices with either of the tire choices - probably the 225s.