The s/c is centrifugal and doesn't shift much air a low revs but the boost increases quite dramatically after 3000 rpm. I think other chargers such as the g lader and eaton flow better at low revs but don't flow as much air as centrifugal chargers at high revs. My experience is with the stage 1 (6-7 psi) kit but I suppose a smaller pulley would improve low down power but probably not significantly. Superchargers don't suffer from lag but you still have to wait for the engine to spin the charger enough to produce a certain amount of boost so I guess it is similar to turbo lag.