A positive displacement blower (roots or twin screw) is going to be very "torquey" great for light to light or drag racing. If your looking to take it to a corvette, out on the highway and want a car that feels like a rocket ship, you should really be looking at a centrifugal (Procharger or Vortec). A centrifugal charger is going to make more horsepower but less torque, which has it's benefits, like, it is a lot easier to get traction during launches. Another thing about a centrifugal, it will pull and pull and pull, while you sink deeper and deeper into your seat, they also have more consistency during road racing.
Back to the question at hand. If I was going to go with one of the two units you have listed there, I would definitely go with the
Whipple. Not only is it priced out better, on the Kenne Bell website the showed running 27 degrees of timing to make 533rwhp. When we installed the
Whipple here at Steeda we were running 14-15 degrees of timing and the car was making 525 rwhp. As you can see you don't have to be so aggressive to make good power. I will give Kenne Bell some credit, he has some great features to his blower like the water cooled casing, and another thing he didn't list what PSI his kit was producing while making those numbers, so those numbers may be great considering. I hope this helps a little with everyone's decision making, and sorry this post is so long, there is just a lot that can be talked about when it comes to superchargers. I could have wrote 3 pages, if anyone would like to talk more or is interested in a supercharger feel free to give me a call at Steeda, ask for Todd.