For the SR20 swap, though, take your time and do it right. A lot of guys run afoul of mismatched and customized drive-axles (I did... and I know of a couple of others, too)... the SR20 comes in a whole kaboodle of cars, which means tons of different length and splined axles... make sure yours comes complete with the proper axles. Lucky you if you get a transmission from a JDM Sentra/Pulsar complete with proper axles and LSD...

Besides that, the SR20 is a great engine... revs high and has good low-end torque. Heck, it's faster than my current 2.0 (well, faster than it was when stock...), and mate that to a light body like the B13... hehehe...