You must also consider that the stock 302 block was not made for 500+ hp. It depends on how often and how hard you will drive it. It might cause issues later on but you should be ok if properly take care of it; don't kill you car everytime you drive it.
For a knock down, no holds barred, brute force of a race, i'd go with the centrifrugal (if i can spell it right

). If you have the correct combo of supporting parts then it should already drive strong without boost. But when the boost kicks in at higher rpm... Mmmmm!
On the other hand, the KB will make your car feel like it has big block engine. Boost is already there all the time from as little as 2000rpm, i believe. Fun factor is awesome! BUT you'll need better suspension to support the boost at low rpm or you'll spin the tires like there's no end.
The KB blower is also more expensive. I look at it as the "Mercedes Benz" of superchargers. Nicely made and great quality! Like a work of art, almost.
I personally went with the Vortech SQ-Trim (centri). When you mash the pedal and rpms build up and THEN the boost... Man, it feels awesome!
Transmission - TKO600. Stronger metal is always good. It will also withstand the the pounding a supercharger will put on it. A good clutch is also important. Centerforce Dual Friction seems like the mainstay but a King Cobra clutch would also do well.