If the info posted in the links posted above are correct, then the CR rear bar is softer than both versions of the AP1 bars, therefore, replacing the AP1 rear bar would soften the rear, which would reduce oversteer (spin potential). However, it would not be a very significant change based on the number in that thread. If you want to reduce oversteer by a signifcant amount, I would get a regular '06+ rear bar. Of course, that is assuming that the specs in that thread are correct.

 

Better yet ... why buy a smaller OEM rear bar from a previous year model when you can just do the "better" thing, and buy an after market FRONT bar that will do a much better job?