Ok, things like this are exactly why we don't have "which are best" threads. The B20b/z is the same block casting as the B18b. If you look solely at compression ratio when choosing an engine for boost, then you really aren't educated enough on the subject to make a valid decision.

The B20 has very thin cylinders from the factory, and of the same type as the B18b. In fact, it is much more reliable to start with a B18b, sleeve it and then bore it out to 2.0L if you're worried about displacement, than it is to start with a B20 and slap a turbo on it thinking you're golden.

The B20 is a fine engine, but it is definately not topping the list of my choices for a boosted platform.