I just happened to have an extra TB from the SRT6 engine sitting around and decided to take a look at it again...

It seems the throat of the TB is pretty darned polished from the factory, so there's no need... Also, these dimensions and photos should help you out... the throat is 74mm and the wall thickness is 3mm. The butterfly valve sits inside the throat at a +13% angle at the base, and -13% at the top. the clearance inside the throat wall is 0.15mm. The thickness of the butterfly valve armature is 10mm and the diameter of the retaining screw holes are 8mm which only leaves 1mm of material on either side before the screws rip through the walls of the armature.

The butterfly valve armature is pressed onto the clockspring mechanism inside the DBW motor housing and secured by a retaining pin on the opposite side... If you ordered a new TB, butterfly valve or associated part from DC, you will be told that the parts are not servicable and only sold as the entire TB unit... So, this means you cannot remove the armature to grind it down...

The clockspring for the butterfly valve is really quite torqued (strong) and is very difficult to press open... It is my opinion, that if you ported the throat of the TB at all, even 1mm you would cause the failure of the housing from the pressure / torque of the clockspring and probably rip the armature and butterfly valve out of it's guide, or crack the aluminum / magnesium casting with the repeated opening closing of the valve... Not to mention the concept of porting the throat and creating AIR GAPS between the butterfly valve... Not good for the idling of the engine...

Hope this helps you reconsider your modification idea... Any other ones you want to discuss ?