I installed a 6XD sequential transmission and I needed a drive-by-wire throttle to take advantage of an ECU-controlled auto-blip for no-clutch downshifts. I have a Wilson Dominator throttle body that has mechanical linkage. I installed a BMW throttle drive motor and connected it, through the MoTec, to a GM DBW throttle pedal. I then used mechanical linkage from the drive motor to the TB. There is no slop (the motor is on front and mid motor plates and the drive motor is on a bracket welded to the cage dash bar), so the TPSs in the TB and drive motor stay in sync. The same set-up is used on some unlimited, injected off-road trucks and can be used with a carb or TB. The decision to do such an installation depends on how bad you want an ECU-controlled, precise auto-blip for road race no-clutch downshifts.
Pappy