First of all, my car has a pretty ghetto rim set up at the moment. I have two really nice 17 inch chrome cobra rims in the back....and then two plain stock mustang rims in the front of my 94 gt. I need to get the other two chrome rims, but i like the idea of getting bigger rims in the back. Would like 20 inch rims in the back be a horrible idea? Maybe something smaller would work. I dont know maybe i should stick with the same size. How much would it effect performance if any? Would the wheels be too big?? Just wondering. Maybe a stupid question i dont know. Thanks

 

In my opinion don't get 20's at all and for the 17's i would be the matching two front wheels OR if money is not an option upgrade to 18's and they should fill the wheel well nicely.