You can buy directly from Weapon R for like $25-30 shipped...

I bought one and put it on 1 day before I got my JG overbore TB and it makes a world of difference IMO...You get more throttle response with less pedal travel.

The JG overbored TB gave a nice response and power gain but it wasn't as much of a felt/perceived gain as the Weapon R rotor...

Now I just have to put my braided ss brake lines and get an Xtreme pressure plate and the pedals will all be equally stiff for that Ferrari pedal feel