RWD isnt worth it in my opinion, it would be too costly! Better option (my opinion, just saying) go 4 motion with a haldex controller.
Was toying with the idea with a friend, found out what is required, tt (180bhp or 225bhp) quattro gearbox and v6 4 motion, rear axle, haldex unit, wiring, fuel tank and floor cut up a bit to accomodate it!
But then again, anything under 350bhp ish, dosnt need haldex, just a decent LSD.