Advantages of the Roe Racing Twin Screw supercharger makes so much torque so early (2,000rpm) that it's like having full throttle always. Rpm doesn't seem to make much power difference. It starts with huge torque and then huge hp takes over. The Twin Screw supercharger is like teh car with a 10L engine. Even the small kit has serious traction issues. The Vec is easy to tune the engine's parameters for all modifications. The Roe looks very impressive sitting on top of the engine, especially the polished Roe. Advantages of the Paxton centrifugal supercharger are that it doesn't start making power until the rpms go high and therefor makes it easy to drive and with the big torque and big power only at higher rpms the traction isn't much of any issue. This type of power is easily controlled and it doesn't need a race car driver to be able to drive the car with a base kit. The design of the Paxton uses auxilary dual fuel pumps and a Fuel Management Unit/FMU to control mixture and add fuel according to boost. The timing is controlled by a Split Second sub computer. The Paxton runs as perfect as stock since it really doesn't affect anything until the rpms go up. Disadvantages of the Roe are that it seems to often have a slight hesitation when easing into the throttle from the cruise/coast position. The Roe does not have California emissions certification.Disadvantages of the Paxton are that it doesn't increase available power all the time.Ted