for drift you need a lot of grunt to break loose the rear traction in an RX8 - if you are going for good weight distribution in the first place, instead of a toyota 4AGE, try finding a Mazda FE and boost it.
you will need to make some items on a lathe, welder etc for the rear suspension to get the ride alignment (if you are a gearhead you will recall the original E30 and E36 BMW chassis were aligned from the factory with a buttload of understeer, it took half hour on an alignment rack to make it oversteer.)