The rally kit is SVT rears and advancetrac (or however thats spelled) fronts. I think all the 05+ have those fronts also. Upgrading the brakes like that won't change your stopping distances by much. It might change the feel of the brakes, and it will change the point at which they fade on a race track, but if you want to stop faster, the most effective and affordable thing to do is better pads and shoes.
some people love their brake conversions, but there are other places you could spend that money to make more of a difference. Tires, for instance, have a huge effect on stopping distance, and you get better handling also. If you can lock up the tires with your brakes now, stronger brakes will just make you lock them up more. Stickier tires with the same brakes you have now will make you stop sooner.