Need New Rear rims and Radials for the GT

[RIO RED SNAKE]

Hey guys, my Uncle Just picked up a 05 GT from Cali with FRPP Exhaust and 10k Miles, it has the original tires on it, and they are dead. I have the NITTO's on my cobra and he wants a set on spare rims to get for the track. I have seen the GT in MM&FF with the TT Ford GT, he has the Cobra R's on there, he has the 4 option BBS rims tha the is going to put stockers back on there, but wants a spare set like i said, what is a good rim with some serious width that will go on that car? do you suggest a 17x10.5 or 18x10/.5 the rears are 19s as of now, and the fornts 18s obv. Thanks