I've used Moroso studs - if memory servers part number 4186....

Remember that you might need to chamfer the inside of your rotors to prevent cracking. The knurl of the stud will contact the rotor and crack/break it. Put a 9/16 chamfer about 3/8 into the rotor.

I've been down this road and took me awhile to figure out why my rotors were breaking. PS - I came off the track at the Glen where you get speeds in the 130-140 range. The rotor basically fell to pieces after the race. Finally realized it was the stud knurl doing this.

The studs are long enough that I can run 1/2 spacers.

Call flatout motorsports - they sell splitters. Located in MA and on the web at www.flatoutmotorsports.com