1992 Mazda Miata - does it have removeable CA emission equipment ?(Orig. purchased in California)

Yes, it has emissions components installed at the factory for sale in California, and they can be removed, but I really don't think you will notice any difference in mpg. There is an air pump that pumps air in to the exhaust to "help with oxygenation to continue the combustion of unburnt hydrocarbons" that is belt driven, but if it's part of the serpentine belt, not it's own belt, it's not worth the trouble. You would have to put an idler in place that is a big hassle. If the pump has its own belt, cut it off and your engine will suffer no ill effects. You might get 1/2 to 1 mpg more. The EGR is the same as any. Much of the Ca emissions package is vapor recovery and will not increase mpg

If you want to mess up your properly operating Miata go ahead. The vehicle was designed to operate with the equipment in place. You will get a "Check Engine" light, the computer will operate in "Limp Mode" and your performance will surely suffer. EGR cools the combustion process by introducing inert gas (exhaust) into the combustion chamber taking up space and thereby reducing combustion temperatures and NOx - your engine will "ping" without it. Leave the emissions stuff alone. Put an inexpensive NOS system on it.