If you can pass emissions one time, you can get classic plates and not have to pass ever again. I did it with my Z before I moved. The vehicle must be 25 years or older.
Also, its pretty easy to pass as long as you have some stock cats to put on. I have a bunch of deletes and the guys at the emissions station are usually clueless about finding them and all they generally care about is the cats and sniffer test. They are usually too busy talking to you about the Z to care about anything else anyway.
