You have $100k to spend on what to spend it on a Subaru? I love Subarus but think that if I had that kind of $$ to spend on a car it would likely be a Dinan S2 M5 (~$90k) that would yield 470 very reliable horspower (and keep the warranty intact) and handle phenomenally as well.
Also, I don't know what the laws are like where you live but I'd like to keep my car at least somewhat street legal. Just a thought.
But getting back to topic...I'd take my $$ to Cobb tuning and have them build you something totally outrageous. They have experience doing that kind of thing (Conebasher). Good luck.
Jay