I have a 2015 GT premium with the performance package and eibach sport line springs with a 1.3" drop in the rear and 1.5" in the front. I have 20x9 and 20x10.5 Niche Verona wheels. I was told they are "medium offset", i guess that means rears are inverted, not sure what a medium offset it. 245/35 in front and 275/35 in rear. I am having a problem with the rears rubbing and bottoming out; you can see where the fender lip is hitting in to the top of the sidewall. I am convinced the offset is incorrect on the rear; American Muscle says they are fine and they are convinced it's the springs or some other suspension issue. Car doesn't sit funny or look/drive like it has suspension issues. I have tried for a week to ask Niche just what exactly a medium offset is, is my set up fine, ect, but they have yet to get back to me. I only have 7k miles. My question is: are these wheels an issue? Is the offset, tire size, tire height, inverted wheel? Any ideas?