I've been offered a set of 997 GT2 Tires and Rims for a very good price, spec as follows:

Front 235/35 ZR 19 8 X 19 57mm offset
Back 305/30 ZR 19 11 X 19 51mm offset

Questions is will they fit a standard S4? I've read all the stuff about offsets etc but still have very little knowledge in this department so I ask the wider knowledge.

 

Both offsets should be good but you'll hafta' roll the rear fenders for sure. Pictures of the wheels would be nice!

 

If they are truly 997 GT2 rims they are 8.5 by 19 (front) and 12 by 19 in the rear.

 

These are the wheels

 

you will need big spacers on the rear (hUGE) and wider fenders up front.

 

look at my pics. those are 11s in the rear with 8" backspacing. (i think that works out to be 68mm offset) and the fronts are 9.5" with 8" backspacing, which is like 83mm offset) now, if you are at 8" rim up front, there is 25mm of problem fixed, and that gets in the high 50mm's, so you might be ok. just thinking out loud). the rears would need some spacer help. a 305 without serious rolling, will hit the inside lower control arm with serious rolling, and 83mm offset rim, it barely fits on the inside and you need some rolling on the outside as well.