Passing the smog check here in CA(from what I hear it is more difficult here) is difficult but not impossible if you dish out some cash. I'm planning on getting an h22a1 motor from hmotorsonline.com because they are about 5 minutes from where I live
If you have it professionally installed, they can fine tune it so that it passes emissions standards. But I would definitely go for the USDM one. JDM stuff is just a little risky when dealing with legality.