If you have collector car insurance in Maricopa or Pinal counties, you're exempt from smog checks. I'm pretty sure the other counties don't require them. In addition, our cars are now eligible for antique plates (the copper ones) that exempt emissions testing, too.
However, some insurance companies have restrictions on when and where you can drive, and milage limits per year. Be sure to take that into account when shopping collector car insurance. I've had both Hagerty and Grundy. They are about equal with their policies. Grundy will write "agreed value" policies, "Which is nice".