I am just thinking out loud here...

Off the top of my head the only thing I can think of that probably wouldn't work from the sti on the 818 is the 6 speed transmission (please fill me in if I am mistaken).

I was contemplating the idea of finding an STI donor (possibly even more likely to be wrecked by a teenage genius) and then selling the 6 speed and purchasing a 5 speed to replace it. Thus recouping some extra cash or perhaps being able to afford an RA or PPG 5 speed in the process. I'm sure the STI would also have a few other pieces on it that would be in demand by the Subie crowd which you could sell of as well.

This way, the motor would already be putting out the power numbers I would be looking for once I swap out some exhaust pieces and have it tuned.

Can anyone think of a problem with this idea?

Also, if this were a feasible option... which year STI's would be optimal?

Thanks for the feedback!