A Megasquirt could actually end up being cheaper than trying to source the original harness and ECU, if you are handy with wiring and tools. And for the power level you want, the stock engine management is really not up to the task. You'll need an intercooler, a better fuel pump and bigger injectors. Maybe a bigger turbo as well, the factory piece is going to have trouble flowing the air at that power level. So you are better off with a stand-alone fuel/spark control to start with.