B series are fun, parts are cheap and theyre everywhere, and you can make good power on boost with them. Unless you go Jakespec style and run 15-16:1 compression on e85/c16 all the time, your not gonna keep up motor to motor vs a k series. k24/k20's are making 260+, thats pretty tought to beat.

Price B>K

Power K>B all day.