Me personally id go with the SR20DET less tuning and more available parts, also it can rev higher and i think it can produce just as much HP as a KA-T but not as much torque.
But if you are thinking of doing a KA-T i would recomend buying a new motor with the least amount of miles on it as possible...
New KA motor 500-700
Turbo kit 3-4,000
all parts needed custom piping inter cooler and other items im guessing 2-3,000
SR front clip 2-4,000
someone to install if you dont know how 1500-2,000
other items needed intercooler guages and so on 1-2,000
someone correct me if im wrong its late and i dont know what im talking about <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sleeping.gif" border="0" valign="absmiddle" alt=':zzzz:'>