With the right torque convertor, and the right setup, there can be a speed benefit. The Comet 30 (if I recall) has a .9:1 overdrive.
Another good benefit is the fact that it since it has a variable ratio, you can get away with gearing a little higher than normal, and the takeoff is still acceptable. So ultimately, you get a higher top end. Case in point- I'm geared at 4.8:1 with 17.5" (measured) tires, and I top out at 72 KM/hr. There's no way I'd be able to gear that high with a centrifugal clutch.
200lbs without engine? That's rather weighty! Give us some more info- frame design, tire size, etc. And so far, I do believe you'd benefit from a torque convertor. My kart's a big chunk of heavy metal, too.
