the owner of bodykits.org has had his jdm ls in a few magazines and he is riding on 19 5zigen copse wheels. but if you throw 20's on a teg that'll look stupid. i've seen the previous body style mustangs on 20's and they have a bigger body and wheel opening and even on those they look stupid. i'd say if you wanna go big go 19's but then you also need to have a rim with a lip or else there's just no point.