Two solutions...

Yes...find a smog station that will pass it...
..they are more concerned with air filter and emissions...so its doable.
I may be able to help...I have a smog place in Pacific Beach that
( depending on who is working!).. is pretty cool with reasonable mods.
Assuming youre in this area !

Second, and easy proper option.
Take it to a California State garage and get an exempt sticker..
They look/maybe test..and put a sticker on the non OEM parts that
viewable... or give you a letter.

I have an exempt letter from them for my exhaust...
...as OEM are not available.

Jo