I am currently building my 818 from a 2007 WRX donor and I wanted to make some modifications/upgrades from stock. I am wondering if there is a good list/guide of parts that should be upgraded/replaced to make about 400 rwhp like the Factory Five 818R. I am already looking at a new clutch/flywheel/pressure plate but what else should I upgrade to get/handle the power? Any help would be much appreciated!