This is all 100% incorrect.

Yeah, and a cam swap will net 100-150+ hp. Remind me again which cam in an S2000 can do that?

Simple. Buy a Ford 6.0 for 10k, put 5k into studding and updating the usual culprits (coolant filter, STC fitting, EGR cooler, etc), then buy a nice OBD2 reader and Torque Pro, and you are set.