Turbo on a ka24de

Hello everone,I’m about two days away from purchasing a 91 240sx coupe and I have a couple questions.
The first question is why do most people swap the ka’s for the sr20’s or the rb20’s,are the ka’s too hard to modify or can they not handle the increase in horsepower.
My second question is that I am thinking of putting a small turbo on the ka and I was wondering if it would be safe for the motor and if so wich turbo turbo do you think would be best(without blowing the motor)and how many pounds boost could I safely run.
Thanks for any replies in advance.

A good forum for this kind of info specifically:
http://www.ka-t.org/forums/index.php

A good thread there to help get you started:
http://www.ka-t.org/forums/viewtopic.php?t=6263

Congrats on the new car!