Originally Posted by qtiger
Using a b16 is a little... odd for a high power turbo setup, as your displacement is limited (by .2 liters) by the short stroke of the b16 crank. Also, you can't straight out use b18 crank and rods because the deck height of the b16 is just a hair lower than the b18s.
For absolute max power, you're going to want to go with a b18c/b18c1 block with either a b18c head or a b16 head. For a buildup like this going with a b18c5 is just useless because you'll be replacing all of the components that were improved in the R engine. Basically, you'd be shelling out ~2 grand for a little 5 on the front of your block and a limited slip differential.
Headwise, it doesn't really matter. You'll get slightly lower compression with a pr3 head, but really just go with whatever you can get cheapest. You'll be picking your own pistons anyway, so you can compensate for that .3 CR difference without any problems.
As for compression ratio, that'll really depend on your goals and tuning abilities but likely it'll fall between 8.5:1 and 9.5:1.
I don't think a B16 is a bad choice for a boosted engine, people make 400hp on those blocks, I don't think this build is going to outreach that power level. And the near perfect rod-stroke ratio can be an asset on not putting a piston/rod through a sleeve.
The C5 block also comes with a factory nitrided crank, which doesn't suck. And you can offset some of the cost, by selling off the internals. Even so, you're right, pretty pricey.
I think a B16, is a good economical choice, and you can just about get away with a stock head.
-PHiZ