Fuel cell question

So I spoke to my smog guy (california) and he said as long as it is going to pass all the tests he throws at it (i.e. evap) that he will ignore that it isn't a DOT tank. He knows we won't say anything because we've gone to him for 15 years and he use to pass my old jeep that wouldn't even go into closed loop and had the check engine light on.



So here is my question. What exactly do I have to keep from stock to keep it "legal". Stock fuel pump? Stock filler neck?? what exactly do I need to have to make it pass the tests.