What exactly are you trying to swap? Engine, transmission and rear diff wouldn't be too difficult, but hubs, brakes and suspension might be. I know a good bit of GD items bolt on, but unsure about the GR. Instrumentation would be a bigger issue. Easiest swaps retain the cluster and ECU from the swapped engine. Just splice the rear portion of the RS harness into the majority of the '11 harness or you'll have some work cut out to make the RS cluster read properly.