GR Parts Catalogues from Japan
 

Here they are.

https://toyota.jp/gr86/option/grparts1/

https://toyota.jp/gr86/option/grparts2/

https://toyota.jp/gr86/option/grparts3/

Regarding SCCA rules... If my understanding is correct because these are the "performance catalogue" only the parts that would normally be ST legal will be ST legal (brakes, suspension, etc.) and the aero parts are all not legal unless a standard model is made with them? Anyone have more clarity on that?

Who's ready to throw paper for the *checks notes* GR door stabilizer?!

Probably the same as the previous trd offering.

I've never seen these before. Do they work?

I honestly have no idea...

it's quite a small difference. I got mine used and wouldn't pay full MSRP. I used to be able to grab the door when it's closed and shimmy it around a bit, so the logic with these is to prevent that movement, lowering the flex of the body during cornering. You will notice a tiny difference the first couple times you hoon it, the door will thunk differently and you won't be able to move it around anymore, but that's it. Not a night and day difference, more a part along the lines of factory skunkworks like Nismo whose mission is to basically extract every gram of performance in the nerdiest and most expensive of ways lol

Essentially all the factory performance catalogs are treated equally to any other aftermarket catalog. There's a specific callout in the rules for bodywork, but an extreme example would be if there was a turbo kit in the STi catalog, that wouldn't be legal either.

Under 14.2 Bodywork:
F. Addition of spoilers, splitters, rear wings, bumper covers, valances, side skirts, and non-functional scoops/vents is allowed provided that either:
1. It is a production part which is standard or optional equipment of a
US model of the vehicle. (“Model” is defined in Section 12.)
2. It is listed in the vehicle manufacturer’s US accessory catalog for that vehicle for normal highway use. This does not allow for parts sold through a manufacturer’s performance catalog (e.g., Ford Racing, HPD, Mazdaspeed, Mopar Performance, Mugen, NISMO, SPT, TRD,
etc).

I'd expect that would apply to any other GR part like the door stiffeners as well. I know that particular part has been mentioned in Miata circles as not legal for ST.

GR Parts Catalogues from Japan
 

Really? The door lock strike plate shims? They actually have a measurable effect?

If it changes the way the door sounds when it closes, then it must have an effect on the way the car handles;)

Sounds like an add for BMW.

I'm assuming they add rigidity and have a 0.0000001% improvement to handling.

You probably being generous.

Maybe or maybe not, and keep in mind that a Miata is an open car. The point however is they aren't legal, and once you start down the road of "that doesn't have a measurable effect" then you have to figure out where exactly you're going to draw the line in all that gray.

In any case, if a part isn't listed as legal it's not legal, so even worse someone can protest you for a part that doesn't help you. This really doesn't happen very often at all at local regions so I wouldn't take them off if that's all that bumps the car up a class, but I've also talked to people who had "just this" then "oh, and that", and "this too" so putting on such a part makes people start to look for other things "that don't matter".