The reason for wanting a 2.0L is for torque and displacment. More displacment has more opportunity for more power. There is no replacement for displacment, no matter what anyone says.
b20 blocks are nice on paper, but in reality they're shit. Ive had friends rip the block off by the motor mount from just launching at the strip.

The ultimate motor for our cars (civic/integ) is still the JDM H22a. Ive heard of a guy with a B18 stroked to a 2.1 running some impressive numbers. Ive yet to meet this guy tho, so that's just heresay. I believe he was hitting mid 11's in a CRX daily driven.

I thought about stroking my motor to a 2.0L SOHC, but it's extreemly expensive, and not good for boost, as we all know, I can't live w/o boost.