Have you got decent suspension on it yet phil?
Helps, although will still be an animal with that sort of power and RWD.
Might be worth considering a Zoo beam though, by all accounts Rods is still pretty controllable despite the power and the RWD only delivery.
My car when i first got it (on the original rs500 shell) was fooking shocking, REALLY tail happy, since building it into the new shell and fitting Koni's + Ahmed springs and replacing all the bushes though its MUCH tamer on the back end, even though it now has more power.