I've done two stage 2 sc conversions, it's not hard, just very time consuming, especially if you want it to look like a factory install.
don't forget all the small items like; an oil catch tank, the inlet manifold adaptors, 2 x long M6 bolts for the inlet manifold, a charge cooler pump + wiring for the pump, moving the ecu, new air intake system, the correct size belt, plus loads of different nuts / bolts / washers, a charge cooler, extra cooling fans, pipework etc, etc....