see the thing about boosting a stock ka is once you get beat by a stock sr, you then turn up the boost past the shitty 6psi then pop.

but as far as a nice set up for a stock block kat i would go with what me and my buddy josh did when we were going kat.

its not super cheap, but its a really good set up

ebay bottom mount turbo mani for stock sr turbo location,
gtir t28 turbo (perfect for ka)
sr injectors (i have a set)
sr o2 housing
sr down pipe
sr intercooler kit (i have a hot pipe with HKS flange)
sr intake hose (i have one)
rome tune
maxima maf

this set up at 7psi shold give about 220 or so hp. maybe even as much as 250 at the wheels. and would be totally sick at 15psi.