Hey SON guys i am purchasing my first car tomorrow a 1992 nissan 240sx blacktop Sr20det full swap. I will be getting it certify’ed and E-Tested what is involved, where do i do it and what is the cost? It is running stock boost hi-flow cat and 3"hks catback with hks power tip exhaust how will i do on etest? should i try and get the stock exhaust or what? 
sorry about the post this is like my third lol.
Most mechanics can do it, Any dealership with a service bay. It would be a better idea to have stock exhaust as the emissions are restricted but may pass. Also, you should have had a safety and emissions done before purchasing it to avoid regretable suprises.
For the e-test you will be fine. It has an sr in it so just make sure the people doing it know that it has a swapped motor and it will be run as a hot-rod. As for the saftey, make sure brakes, tires, lights, windshield, all the basics are in good working order and you should be fine.
stock exhaust wont make a difference… only haveing a stock cat vs highflow vs no cat would make a difference