I have a 90 lx with 2003 cobra replica rims and tires 245-45-17s all the way around, same size all the way cause I wanted to rotate my tires. American Muscle .com is where I bought them they have a fit guide and you can call them they will hook you up. Or you can privite message AMNick on this site he works for them but those tires and rims will fit your car if you buy from these guys they will have the proper backspacing. The only reason I didnt go with the 275s in the back is because i wanted to rotate and they would have touched my exhaust pipes and I would of had to rebend them. But I talked to these guys on the phone like three times so Iam positive these rims and tires will fit your car. 
__________________ 1990 5.0 lx, 302 saleen votech intake, bbk 75mm throttle body, cold air intake, bbk headers and exhaust all the way back, bbk traction bars, 373 gears, aod with a shift kit | 
2003 Mustang cobra rim best tire fitment need help 
