From my understanding, twin-screws setup correctly are just about as good as turbos. Turbo's need an IC to be any bit efficient (edit: actually, I think under 4psi I think they are fine without an IC), and a twin screw could give a psi or 2 more before needing one. Twin turbo setups are good, but it's the same as upgrading to a bigger carb, just the ability to pull in more air, same psi of boost. As for the juice, it's good, cheap and easy, but also dangerous and usually needs fuel upgrades, port job and a new cam to be as good. With a blower/turbo, the force of the air will open the valves better and ram air in, but with NOS, you need a cam, RR, springs, and valves to get the air and fuel in since it uses the vacuum effect.
I'd take a KB over a turbo not always for the higher numbers, but because I like the sound of the twin-screw and not the BOVs.
Just because someone has more HP/TQ doesn't mean they will always win, it's how early does it kick in and how long does it stay at that. I've seen dragsters win but had lower speeds, it's because they get to that speed quickly and maintain it till the end. That's how my 193 bhp V6 can kick my dad's 79 230 bhp 5.7L even if they weight 200lbs difference. I got torque lower and longer than he does.