Good luck getting a straight answer from Pettit hehe. (though I called so many times, they probably got tired of me calling and went an got the info afterwards. This was a year and 1/2 back though, when the flares first caught my eye)
Couldn't beat it out of Forgeline either. Everytime I called, I got the same line - "we send many sets to Pettit, and don't have the time to look it up". Basically, if you not going to buy our $1000-per-wheel wheels, we don't have time for you.
The pic above is of SPO-RX7s car, and he indicated to me once awhiles back his rears are 18X12 +25. Not sure of tire size.
More info on fitment in these two threads: