One of the problems I've encountered with building the Miata has been a lack of industry support. It's a weird problem, because there are thousands of Miatas racing in America, and undoubtedly many more around the world.
One particular area that's not well supported is seating. The Miata has a narrow seating area, and the options are somewhat restricted on what you can mount. But that's not really the problem. The problem is that nobody, and I mean nobody, makes a standardized mounting platform for seats.
In the BMW world, Turner Motorsports makes this trick little plate that mounts to the factory floor holes, and provides hundreds of threaded holes to bolt seat adapters down. It's perfect for a large number of seat brands and shapes.
I spent months searching for solutions, and I called a few seat manufacturers to see how people were getting the job done. Solutions ranged from the simple to the terrifying. I heard that some people use the factory seat rails and just buy narrow enough seats to bolt right onto them. That didn't seem safe with the seats I was using. Other solutions involved grinding off the factory mounting tabs and putting the seat on a 2x4 bolted through the bottom of the car. 2x4 = fire hazard under my butt, so that was quickly ruled out. The most bizarre solution involved grinding off all the factory mounting positions, including a structural member...no thanks.
I went with a modified version of the first (factory rails) for the driver's seat, putting side-mount rails on top of the factory sliders. This gave the seat some extra strength because any load put on the aluminum seat would be shear instead of tensile. Blah blah blah. Anyway, it made the seat way too high, such that it intersects the rollbar. That's bad.
For the passenger seat, though, I decided to show some ingenuity. I ordered angle aluminum, cut it to length, and shaped it to fit the factory mounting tabs. Then I drilled holes in it to side-mount the seat. Perfect!
Well, not so much. I just found out this morning that in cutting the aluminum, I was putting my life in serious danger. Turns out aluminum dust is not just highly flammable, it's also a serious explosive when wet. You see, aluminum flakes, when introduced to moisture, heat spontaneously and emit hydrogen gas. There's an ignition temperature of about 360-C, and then presto: an extremely powerful explosion. The stuff is so volatile that it can detonate a vacuum cleaner just due to static electricity.
And here I am just using a big ol' 7" cut-off wheel in the back yard, leaving the dust to sit in the rain. Good grief, I rock!