They're both superchargers, the difference is how they're driven. To cut it down to basics, a turbo is more efficient because it uses "free" energy in the exhaust gas heat. Turbos are more expensive, so any savings is moot. Crank driven superchargers like the Vortech take power right from your crank, reducing overall output in comparison to a turbo. But because they're crank-powered, they deliver boost right away, helping your low-end significantly. When you have a motor that only goes "bang" twice a revolution, getting extra low-end torque is a very, very good thing!

If you're looking for the best times at the dragstrip, go with the turbo. If you want a more streetable car, get yourself the Vortech. One second difference in the 1/4 mile is HUGE, so you need to decide exactly what your goals are.

To get a 10-11" FWD car on the track, you're going to need to do a lot of things to get power to the ground that will keep it from being street legal. It sounds like you're looking to go racing, so buy yourself a trailer, and start gutting your car. Use the low compression pistons, and turn up the boost. Naturally you're going to need bigger injectors and an aftermarket ECU, so you don't blow the whole thing up.