Yes, you need a re-sleeve if you go 2.0 liter as you will bore out more then the stock sleeve has to bore with a 2.0 liter, and no you should not use an LS block for this application. And, yes I suppose you could stroke it for more displacement, but you're gonna start running into some outrageous expenses. I've never seen anything more than a 2.2 liter be sucessful on a B-series, though, just becuase I've never seen it, doesn't mean it's not possible.

Any way, got to get to class, sorry I couldn't elaborate more.

Aj