KB is nice, but there are a lot of factors you have to put into place as well:
-Do you want constant tire shredding power at all times? (TwinScrew > Centri)
-How much $ you willing to spend? (TwinScrew > Centri)
-How mechanically experienced are you? (Centri > KB)
-How much HP are you looking to max at? (generally Centri's have higher # potentials)
-Is it a DD? Centri's are nice as DDs as long as you can keep your foot out of the hole.
Also, keep in mind you'll have to go direct through KB if you want to do the install. MPH's Mongoose kit CAN NOT be drop shipped which means you have to have them install it in Georgia.
Yea, I'm a little biased here, but you need to do a lot more reading before you make this decision. In the end, it's your car.
My mongoose Vortech + all guages came to ~$4,500. I can get an i/c and potentially push my block to ~400rwhp and still have spent less and make just as much if not more power than the KB 1.7 guys. Yea, they will spank me light to light, but I don't street race so that doesn't bother me.