For a turbo app, defiantly the B20 CRV over a GSR B18C1. But can I ask, since you have a B18B1 LS to begin with, why spend money to junk it for a CRV's B20? The LS is a GREAT GREAT engine to turbo. Arguably one of the best to turbo. You already have the LS tranny, which is perfact for a turbo app due to the longer gear ratios, keeping the turbo spooled longer. Also, a B18B1 can take 12psi on stock internals. It's a very strong engine, with a strong block. The Comperssion Ratio is low enough too, at 9.2:1, so you are fine with that. Why spend money to dump the LS and put in a B20, put that money into making your's an LS turbo. At 12 psi, intercooler, You should be looking as 250 hp or so, and that should be plenty fast for you to start. If you need more, strenghten the internals, close the deck, increase fuel flow, etc, and turn up thr boost. The LS is the engine of choice for many people when wanting to build a turbo'd engine. If you didn't have one, If you had a Civic DX with a D15B7 lets say, I'd say look into the B20 if you want to. But you already are starting with a perfect turbo motor, the LS. Why spend money to swap in the B20 when your current motor is a great turbo motor. That's just money you could have put towards the turbo itself. If you do get the B20, I know that putting in LS cams puts out a little more power. There's a guy in jacksonville with a 12 second turbo'd crv, he put in LS cams. Don't kid yourself though, a Turbo'd LS can be a VERY fast motor.
Also, the CR-Vtec is the same idea as an LSVtec. A B series Vtec head (usually a B16A or B18C1 head) matted to the CRV or the LS Block.