Hi ! It depends on how stiff your suspension is, and how the roads are that you,re driving on, but the offset of the Escort rims is way out of hte acceptable tolerances. The Sierra have a standard offset of 40mm, and the Escort rims have 25mm, so you are increasing your track width with 30mm, which won,t be any good steering geometry.Another problem is if you hit a pothole or something which compresses the suspension very much. Then you maybe will damage your wheelarches even if your suspension is uprated. One solution would be to cut off a bit on the backside of the rims to get a better offset, but check that your wheelnuts don,t bottom out on the brakedisc first, and that there is enough material on the rims for strength. Good luck!