id go with a b18b or a b18c1. either way, build and boost, or just boost on stock internals.

b18a/b- good torque, ok hp, great for turbo, very abundant, easy to install, cheaper that other b18's
b18c1-good horsepower, nice stock or with bolt ons, but expensive and higher compression then a b18b
b18c5- very nica N/A motor, not good for boost. very expensive and harder to get ahold of
b16- basically a dohc d16, dont feel the power until u rev it up. ok for boost, but also has higher compression, easily found and abundant, relatively cheap
h22-more modification is needed for an h22. there nice because they can be found relatively cheap, until u have to buy everything extra for the conversion. weigh a lil more, but make up for that with power. forged pistons can not be used unless u have the block resleeved.
k20- very expensive, swap is alot more involved then a b18/16 and even an h22 rom what i hear. after all is spent, you could have built a b18, make 400+ with a turbo and still have money left for a case of beer to chill with ur friends.