I think what Stan is saying is that it can definitely be done. My car is living proof , but the build is complex.
Exactly.
A WRX turbo motor with a stock ECU makes about 300 hp +/- and is an awesome thing. It's also heavy, complex, and expensive. A 400 hp WRX is completely possible, but a chipped turbo Subaru is gives back a lot of what guys turn to with the platform. That's fantastic as long as a guy knows what he's getting into. There's nothing reliable, stock, or easy about a 2.5L/4 huffing 20+ lbs of boost.
There's a point where the bell-curve to get "more" takes a pretty hard turn in the upward direction, regardless of the platform chosen.
I'll never try to make a value-equation argument for a Type 1. Once you are past 140 or so HP, power comes at pretty great cost. Pursuit of "more" takes a guy into waters where the boat often has 4 holes and 3 corks. Moving the corks around to fix one problem opens up another. It's sometimes like whack-a-mole with money, and nobody understands why a sane man would play the game.
But I think it's important to remember that you're playing the same game with a 300+ hp Subaru, which may or may not be substantively "better" for every single application.
My point was exactly what I said in the original post. A 180-200 hp Type 1, properly set-up and geared is nothing to trifle with. On the right road, it can made to run away and hide from cars with considerably more power. This was the spirit of the original "giant-killer" 356: lightweight cars putting down adequate power, adding up to a sum greater than it's numbers would indicate. It doesn't take 400 hp to go fast on a twisty road.
I disparage no one's choices, cars, or engines, as long as guys are using them in a way that makes them smile.