k, well in response to everyone putting down the SR20DET swap.. does anyone even realize the difficulty a new-to-the-game tuner is going to have just tuning the car to accomodate the turbo-charger? You say dropping a new engine into a car isn't a job for noobies.. but really, is installing a turbo-charger, then having to adjust ur AFR, ignition timing, etc. going to be any easier? When i was 16 i did my first engine swap on my toyota truck (which i still have (L) ).. AND it would be alot harder to accomplish then an SR20DET swap, seeing as the engine i installed was a small-block 305 from a Trans-am. So before you start blowing everyone else out of the water with ur statistics and ***, take a look at the big picture... the guy who started this little chat obviously doesnt have the experience to be doing anything too comprehensive to his car.. at least not yet. An SR20DET swap would gain him more horsepower right off the bat, without having to modify air/fuel ratios and all that other good stuff. IF he gets serious about it later on, then he can just keep the old motor stored away, tune the SR20, and if it doesnt work out, then he would already know how to swap the motors.. he can just go back to the KA.  

Put in the 350z engine........people are doing it lately.  

Ok both the SR & KA are good motors. The SR is the number one motor for drifters today, the motor (since it has a shorter stroke) has a higher rev which is great for drifting. The SR record drag is 7.25 178 mph @1/4 mile. The SR also has its downfalls, well its not emissions legal, valvetrain problems, spark plug issues and parts availability.

The KA pretty much is a stroker engine. It has a long stroke for its size. The Ka is a heavier motor since its cast iron. There is word of a 1000+hp KA-T 240sx, but I'm unable to find it. Ivan P. from KA-T.org has the quickest KA-t so for (9.07 157@1/4 mile 716whp 43psi). The Ka has its issues to timing chain, rod & main bearings, noises from valvetrain,ect.

Money wise, quick horses and experience go with the SR its straight formward drop it in, do some wiring and little things and go. If your wanting to keep the KA, it can be pushed to 500+whp stock internals. If rebuilding it is what your planning high compression piston and eagle rods for N/A and 8:0:1 8:5:1 pistons, eagle rods, 264/264 Cams, plus a good turbo kit. What a Beast!!
The Ka may cost you some $$$ it can be stronger in the long run. The SR is fun very tunable and easy to work with sometimes. Its all up to what you want in the future, plus the cost.