I am also in California so I have to worry about big brother and the smog laws. I was just on the Whipple site and did not see anything about 50 state smog legal.
I am seriously thinking about it. My 2018 GT should be here in a couple weeks. Still need to wait for the Roush S/C to come out. Already ordered some 10.5x19 front and 11.5x19 rear wheels. They should get here about the same time as the car.