18' homii and like reptile said.....drop it about 2 inches
why would you put 20's on a stang gt......it's too much and the dude who said that it didn't affect the performance lied to you.......20's on a gt would hurt the performance and the ride will be bumpy as fuck....plus the tires will be expensive and more chances of you break'n the rim
20 on a 94-96 impala or other big body would look sick but dont belong ona mustang gt imo