loessl4

I have an 2008 is350 and have had no luck twice. Once buying 18's from tire rack for my winter tire set. Lexus dealership told me they didn't fit. So I just put the winter tires on my stock rims. So I've been looking for staggered 18's or 19's quality CHROME rims for my summer tires and bought a set from tire warehouse...Again they didn't work. They contacted the brake calipers in the front. The backs fit fine. The Lexus dealership has not been very helpful as of yet. How do I go about getting rims that will fit. These websites say certain ones work...but I been burned twice. What info do I need to be assured that what I get will work? Any suggestions? Thanks in advance.