[WorkInProgressK]

For AutoX, to be competitive, I suggest running stock 17 rims to be classed lower(stock).
If you want a little wider finding the S rims which are 9 wide rears would allow you to run 265's. The other 17s will bump you up one class and you will be less competitive.

Extra tips.

Run M030 ROW with stock front plate and stock springs, camber plates will bump you to the next class. The springs are a gray zone because they weren't official original parts, but are still available through porsche.

Don't get a seat, that bumps you to the next class. Get 6 point harness and run stock seats.

If you are not worried to compete in a higher class (STX, i think its that, basically facing against S2000s.) Use the 8.5 and 9 rims with a square tire setup. (same tire front back this allows you to run the RS4s ) Get a seat and 6 point harness, we have an incorporated roll bar which makes it easy to setup. M030 row as you planned with camber plates and maybe larger bars. I would do rear first for AutoX or Front first for track.

Have fun.