i pick up these (2) dunlop for $140. they're brand new. my question is, it's going to be little hard trying to find another used set with same brand name to match up. will it be ok if i get another 2 different size 18? i'm going to put 255/45 up front and maybe 245/45/18 on the back? this just going to be temperary until i can afford 2 new 255/45.