It'll be much more expensive and you'll have to pull the motor in your car either way. If you want to just put a B20 in your car and not do much to it I don't see the point, you won't be significantly faster. It's essentially just an LS motor bored out to 84mm from the factory. The heads are pretty much the same, the cams are the same, the rods and cranks are the same, etc. If you get a B20B (97-98 CRV) you'll actually have less power since it only makes 126 hp. The B20Z (99-01) makes 146 hp but is generally harder to find. You can get a much bigger boost in power from a nice set of cams in an LS motor (after you've done the requisite i/h/e) than a stock B20Z.

Now the part which I tack onto every sort of general inquiry like this: what exactly are you trying to accomplish here? Think of a performance goal (either an hp figure or a 1/4 mile time or whatever) and then try to figure out how to meet that goal. You'll get much more useful responses.