I didn't have any significant problems doing that. As I recall, there is a 'minimum mileage' requirement for out-of-state cars brought in (unless you're moving into the state). I don't remember for sure, but I believe it was 7500. Double-check that if it's a very low-miles car. The emissions requirements themselves (passing) are not a problem. I had to get it smog checked myself in CA prior to titling/registration there; which incidentally you aren't allowed very long to do after bringing the car in-state. As I recall, that's something ridiculous like 10 days. There's also a visual inspection done at DMV at time of registration. My car also had to be at least safety inspected, and possibly smog checked in the state of origin (Utah) at the time of sale.
As long as it meets the mileage minimum and it's a 50-state emissions car like the NSX, there are no big issues. Just don't miss the deadline to register it after you bring it home, else they'll charge a penalty.
- Richard