Going to a lower gear without a pure drag tire just spins the tire easier. If you have enough power to spin slicks, you would do the same and move to a taller gear or a taller tire. Turbo Tom is going to switch to a taller 26" slick to do tha same thing. The advantage of a taller tire over a taller gear is increased foot print, which is why Tom switched to a lower gear in the first place.
For a street tired car, the taller Zetec gear will help you hook up easier because you can grunt the engine into pulling the car instead of going up in smoke. It's a LOT easier to launch.
