I didn't mean rwd only but having the rear axle "locked in" with the front so they spin up equally when under power while turning and potentially drifting. WRX's with similar straight line performance to your car are quite handy at autocross as they really put the power down exiting corners, especially the tighter ones.No - the Haldex awd system is never going to be able to send power back without power to the front. You can knock out the stability control which helps it slide a little. Funny you mention the track - I'm goign to a driving school this weekend at VIR in VA with it.
Have fun at the track, VIR looks really fun and not too hard on the brakes as I imagine you can easily overpower the stock ones with the acceleration you've got.