5.0l are a little disapointing out of the box. However with the KB if you do it right WOW. The problem with the KB is you have to do alot of other mods to make it run right. Sure you can slap it on a pure stock motor but if you beat it you will blow something in under 1000k. I assume you will get the blowzilla?
If you dont do some headwork and get a good set of headers alone with the rest of the exhaust you will be blowing headgaskets ALL day long once you get into boost. I know all about that.
You will also need a new MAF, TB, Injectors and boost a pump. I think that kit includes a KB chip but I am not sure.
Dont get me wrong if you do all the right mods before you install the blower you will be around 450-500hp but thats ALOT of money.
If you have questions about supercharging or mods PM I just spent about 8$k and alot of time to get my blown bird running right