Yeah I was gonna say no to the 275 out back. I have a set of cobra 17x9 and 17x10. 275 out front and a 315 out back. I like to see this car with those sizes on it, cause I am gonna try the same thing.
I'd put good money that it has a panhard bar on the back. The PHB lowers the roll center, and a side effect of that is the top of the tire tucks into the fender better when the body rolls over it in a turn.