Brad some good points there, but some wrong ones too:
Quote:
First, the cable fulcrum is different-which means that XX amount of movement in the cable will not translate to the correct amount of rotation at the TPS. This means the PCM will be getting incorrect info.
This is simply wrong. The TPS is connected directly to the shaft which is connected directly to the butterfly. Hence the voltage reference vs. the angle of the butterfly will remain unchanged when converting from the SVT TB to the GT TB. Think about it. Sure the "cam" on the two TB is different. That only changes the amount the butterfly opens with regards to the amount the pedal is depressed, but the ECU is blind to this as there is no reference to the pedal movement.
You are correct though in that the 65mm GT TB need some customizing to make it work on the 2.5L engine, like positive stops etc.
In the end the BEST option for a modded 2.5L for simplicities sake is to optimize the SVT TB - the gains won't be nearly as much but then again the airflow through the SVT TB is probably more than enough for a non F/I 2.5L engine.
For a 3L a 65mm, IMHO, is the best option. 
