This isn't turbo or performance related, but it may be helpful to a few 99-00 owners who want to have the same driver's side window auto down feature that the 01-05 Miatas have. The instructions have been online for a while, but I figured that I'd document it and add a few helpful pictures as well. If you want auto up and down for both sides, Duetto Motors sells a pair of modules for $95/shipped that you have to wire in.
First off, acquire a window switch assembly from an 01-05 Miata. It's on the right. On the underside you'll notice that the harness will plug in from the opposite side, a little bit more tricky when it's time to install the center console, but still easy.
Here's the power window harness, even though there are only 6 wires, it might be a good idea to label them if you don't have a lot of wiring experience or a good memory:
A pick will make this project a lot easier, definitely recommend picking one up (or a very small hobby/jeweler flathead screwdriver). Remove the plastic retainer from the harness as shown:
Then, using the pick, remove each wire from the harness. Reverse the wiring and reinstall. You want this:
Install the switch assembly into the center console, plug the harness in, and enjoy having a driver's side window that automatically rolls down. That's all you have to do.