If you're planning on putting a fat (305+) rear tire on those rear wheels, and you're lowered, you're most likely gonna end up with tire-fender contact back there, over bumps.
An 11"-wide rear wheel on these cars should really be closer to 60mm offset for them to tuck inside the fender over bumps or if on air-suspension.
As far as the front fitment, I believe they'll work just fine.
The factory Shelby '07-'09 wheels are 18x9.5 with a 45mm offset, so they stick in further by 10mm, and they obviously still fit fine