Either buy the kit from brembo or buy an ss rear axle its cheaper to get the rear axle BUT it has the 5 bolt pattern as far as I know other than the bolt problem it should bolt right in. The axle is cheaper by the way ive seen them as low as 700 but he kit I havnt seen for under 1000.
I believe there is a company in the process of putting one out. I read something on CSS.net about it and there were a few people who've done it custom.
How are you hosed either way? Since you have 5-lug, can't you just replace your rear axle with one from an SS and you're set? Then find some larger rotors for the front...perhaps do an SS swap up front as well (not sure what's involved in that).