I know its been asked before, but this is kind of a unique problem.

I bought the car, its a tossed together car with tons of different crap than came with it, but somehow it all works for the most part.

I have a 1990 GTU N/A (originally) with the sports package (4-piston front, single rear), 5-lug all around, a stock N/A 1990 rear differential (adapted half-shafts) and a 1988 TII JDM swap in it. This also has the BBS (vert?) wheels.
http://civerus.imk.cx/pictures/rx7/DSCN1578.JPG (Old picture, been painted and fixed up quite a bit)

Now for the problem, when I goto the autoparts store and ask for wheel studs, they have the one number for the stock 1990 GTU, which is way to short of a stud. In all honesty, I have no idea which ones to get, the ones on it now have a giant M stamped on the head, and the head is also larger than most other cars studs (wow this sounds wrong).
The autoparts store gives me ones with a smaller radius head, and a smaller length, but the correct press-in diameter. I really need to find out this information because my right-front has only 3 studs atm out of 5 (sick of tire shops and damn impact wrenches).

Also for the love of god, if anyone knows where I can find 4 of the centercaps for the wheels, I would love you forever.

 

Here are the factory wheel studs.
http://www.mazdatrix.com/WHEEL1.HTM

Regarding the center caps. Hawk the for sale section, or put out a want to buy.

 

I was hoping to pick up a stud from Summit Racing. Does anyone know the actual specs of the stud such as overall length, knurl diameter, knurl length, etc. so I can just run by and pick one up?

 

I put ARP extended studs in my car and they're awesome.

Here's a comparison of the two.



Then here they are installed.

 

 

I only have one bad stud, I just want to replace it with a properly sized stud. There are a million options!