Hi all, I am configuring my model X order, and everything seems to be necessary. I live in Bay Area, I don't know whether the air in general needs the $4500 premium package to get the HEPA filter. Well, maybe sometimes I will travel to LA, or some places near the cows and pigs and fertilizers. But adding that $4500 will make the after tax price over $110,000 ... a psychological threshold that I cannot sustain. Any comments are welcome.