So i've got one Brand new Potenza RE750, planning to get one more of those, then 2 other tires(cheaper if possible) to run in either the front or back(whichever is better).

These are going on 17" S4 wheels

what are your thoughts?

You would have different levels of grip front and back, complicate that with each tires grip changing at different levels in different temperatures, one pair wearing faster than the other, one pair better in dry while another pair better in rain, etc, etc.

You want your handling to be predictable and the balance of the car to remain the same as temps and weather conditions change.

i'd heard you could run a front/back set up that would work okay. But thank you for the further explanation!

Sorry for the LACK of thanks in my initial response!

and it was pretty ghetto. But it saved me a few bucks and I still got around town just fine. I wouldn't recommend it for any car that isn't a complete POS though, and especially not for anything with AWD.