[Beware-of-the-Phoggy]

I've got the performance non-run-flat staggered setup on my M240i. Traction on them has been phenomenal—I'm yet to spin any wheels while accelerating from a stop, even in heavy rain. But I quickly learned that the staggered setup understeers, lacking some grip in autocross.

When buying new wheels/tires, I think that going with 8.5" in front to run a square setup would be my ideal: better steering, able to rotate tires for longevity. But that'd be a no-go if I do more autocross, since increasing my front wheel width would bump me out of the stock class (FS).

I could, however, go square by running 8"-wide wheels in the rear and remain in the stock class. As I understand things, more rubber typically equals better grip. But running square would reduce understeer.

Also worth noting that for street use (or maybe running all-seasons Nov/Dec–Feb just for the temperature, not snow), the wheels I'm drawn to are only available in 8" wide.

Compared to the stock staggered setup, what should I expect if I run 8" square wheels? (with spacers to maintain clearance/fitment)

[XC3LLR8]

Does the fact this car comes stock with 8.5" fronts if you option for the ZTK package not matter in regards to bumping you out of the "stock" class?

[Beware-of-the-Phoggy]

Originally Posted by XC3LLR8

Does the fact this car comes stock with 8.5" fronts if you option for the ZTK package not matter in regards to bumping you out of the "stock" class?

Since the 8.5" fronts are packaged with the 9.5" wheels in the rear, plus the rest of the ZTK package (brakes, oil cooling) I'd have to upgrade ALL of the ZTK elements in order to stay within the "stock" class.

The rest of the wheel options are a-la-carte, not packaged together. So 8.0" + 8.0" or 8.0" + 8.5" are allowed.

Rules also permit going +/- 1" in diameter, and any rubber (rated 200+ treadwear) you can fit onto the wheels you've got.