On a GTD a number of guys have done what Julian has done with success. I am still on the standard item. The thing to watch when doing a floor mounted version is to make sure the master cylinders clear the chassis rail in front of the pedal box. If you can acheive that, and it is easier for short drivers than tall ones I guess, you are onto a winner. My expereince would say to lose the servos and keep the standard pedal box is not a good move.