if you live in cali, and youre worried about emissions, you'll have to go w/ the USDM sr20de, or just stick w/ the ga16de. i have heard that it is legal to put in another motor, as long as it is newer year than yours, and you do have to have all of the emissions things like cat and stuff... of course, tuning your stock motor would be the easiest, but like the previous post, you can source an sr20de for fairly cheap. it is much more than just the motor tho. (all the accessories, halfshafts, ecu, and a lot more) if you wanna do this, youre only gonna get 30 more horse (stock sr20de), which you should be able to get w/ all the bolt-ons, cams, ecu, etc. and there are so many threads about this, its redundant now. so just use the search button, and type in sr20 swap or something.