the K series are awesome, it will have alot more torque then ur b18c7. but i think its not worth it to put it into ur dc2r. if you want more power maybe u can go down the turbo path. if n/a is wat you want sticking with the b18c7 is good enough, spend the money on the b18c7, such as cams, etc etc.
if you can get a hold of a k series it will be better to get it put into ur crx or get a eg hatch, those things kill!!. i think a eg hatch with k20a can kill an evo, but stock...lol anyway put the k into a lightweight car to get the most out of it