I would have made them take it back and threatened them with legal action. First of all, they lied to you by claiming a setup that the car come with STOCK (mine came with 225/40s square stock) damages the car. When this happens, you document it in a statement, verify who said it, sign your statement verifying it as a record of conversation or whatever. Then you send it to them in a document, so there's a document trail started, etc. Once they start seeing their words "documented", they tend to fess up real fast and do the right thing. You'd cream them in court with crap like that going on. It's what court is for.
I had a problem with my Camaro SS and they just started making up shit at the dealer and then started accusing me of ridiculous stuff. So I documented it and put it all together in an evidence package, sent it to them. What do you know, 3 days later my car is detailed and ready...I had told them they had the two required chances in the lemon law and that I was giving them the final chance (also in the lemon law) to fix it (has a day limit on it). Unfortunately, you gotta do stuff like this, because people don't do the right thing.
In other news, I'm now running 255/40s on 18 8.5, squared. It's 0.2% different diameter than the stock 225s, which is basically not even enough to get my speedometer to read any different. Got about the same clearance on the inside as I did with the 225s, since I went with 35 offset. It ain't much, maybe 7-10mm max, but it's enough.
