1. I drive an X. No $400 rear diffs for an X.
2. Rear diffs are not allowed to be changed in STU SCCA autocross class
3. Not sure this is an issue with the X honestly... the rear rotates like a champ with 2* of camber (more like an 06 STi, less like an IX MR from my testing this weekend).

 

haha, didn't see that, thought we were discussing a IX. forget everything I said.

the active diff in the X is the best of all worlds.

 

I understand that, I was wondering if he was refering to camber or toe.
Every car is different, get a tire pyrometer record everything and combine data to come up with the best setup for you.

 

Excessive camber can lead to less braking traction at high speeds. I have noticed this when playing with my alignment at the track. Different setups will react differently to the camber though. Hope you find something that works great!