Hi I'm new to the forum and am new to GM as well. Anyway I was wondering about my 2006 Cadillac STS I just purchased. It came with staggered 18" tires with 235/50/18 on front and 255/45/18 on 8" wheels. The dealership put 245/45/18 on all 4 but I switched rear to 275/45/18. Is this a rare option? I've seen on here people say their STS have staggered wheels but their 17". Those same people said wheels are 7.5 and 8.5 but my book says their 7.5" and 8". Also my Caddy is black on black and I want to go to black wheels with polished lip instead of chrome that it came with. But staggered black wheels that fit my car are hard to come by. I found 7.5,8,8.5,9.5 but only in same front and rear. I don't think the 275/45/18 would be a good idea on 7.5" rim or bigger than 8" rim up front. Thanks in advance guys. I love the site. Oh one more thing I went to a muffler delete with 4 1/4" tips that won't void my extended warranty 2yr 24,000 miles or my Engine For Life Warranty thru Dealership? Rest of exhaust is stock.