My shop works on Nobles everyday here in California.
I own one as well as just sold my NSX the other day.
They do not require emission testing if registered correctly.
I view the two very simply-
One is a luxury race car (nsx) and the other is a race car with air condition (Noble).
In my experience with Noble owners, they seem to enjoy having a "toy" to play with while they are out driving their Ferraris, Posrches and other exotic car.
One has to remember why they are buying one vs. what they are buying it for. It's a lot of fun for the right reason and the twin turbo V6 is a definite plus.
If you are local, or even not so local, please come by or fly in.
Here's a few pics. of cars we've finished this year. I think we've worked on 30+ in the past 10 months.
You can phone my shop if you have any questions.