[Porsche-O-Phile]

Generally speaking the 8V heads will work better with forced induction. There's a guy over on that "other" board who goes by the username of special tool, he's quite knowledgeable in this area and has done a lot of R&D testing for Vitesse Racing (including their "sledgehammer" 8V head). I'd recommend doing a search on those few names/phrases as a start...

There are a couple of 16V turbos running around out there (3.0L typically) but they are INSANELY expensive to build and when you can get 400+ RWHP out of a 2.5L, I don't really see the point unless you like throwing big piles of money at diminishing returns just to get bragging rights.

My advice would be to research the many fine options available for 2.5L builds on existing 951 engines, get one and transplant it into your "S" if you want, or better still just buy a 951 and build it up. For $10k you can get a nice one, then spend another $10k-$15k in mods and you'll have a 350-400 RWHP turbo car that will hang with just about anything out there today.

If you're hell-bent on turbo-ing your existing 16V car, yes it can be done, but it's not the easiest (or cheapest) way to proceed in the long run.