It's taken nearly one and half years but as of Friday night, the 2002 Miata LS 5-speed is officially mechanically 100% good to go! Mr. Polar Bear in disguise and I took apart the console to get at the shifter so we could change out the turret oil and replace the worn out plastic bushing with an aluminum piece. Oil was really dirty and black and the plastic bushing was developing lots of grooves in it from all the wear. It engages gears a lot better now, a bit less notchy but more certain I'm banging it into the right gear.
Also removed the hardtop to replace the loose forward latches with a set of rare 1990-only glossy-black latches. Why are they special? You'll notice 99% Miata have a semi-gloss/matte black latches and they tend to wear out and stop locking, causing tops to go airborne at speed. Early 1990 Miatas latches are a gloss black and rarely developed the same worn unlocking problem. I found a salt-pitted set from a wrecked coastal car, grinded off the corrosion, and painted them semi-gloss black. Now my 1000$ investment won't eject itself and become a 600$ investment.