check with your local emissions shop or SMOG test center, also check to see if the headers are CARB approved, that basically means that it will not let out toxic fumes and is SMOG friendly thus making the headers LEGAL!
Yep
That's a good sign. If you have to take your car through some sort of emmisions test each time you renew your tags, that's a bummer for performance freaks. Talk to a custom exaust specialty shop as well, they may have some helpful hints or tricks, know what I mean.
I happen to be fortunate and live in a back woods small town and we don't have to take our cars through anything to get tags etc..
So anything goes here basically. Guess we are spoiled here.