Yes, I can totally understand "building mods" but really unless you have those other mods is it really gonna make a difference...I can see the "bonus" potential though...throttle response, if your cable is loose(factory is not neccessarily "loose" but not tight either)...ummm
BTW...I'm gonna do this my-self(if its free, its for me) good cheap mod...really what could it hurt, unless you dremel a little too much...

But no-one has any figures on this? Throttle response depends entirely on how quick it opens...I highly doubt that all the airflow the world would increase the actual airflow to the TB if the 'fly wasn't open...
Throttle response[depends on]cable response[in which you have to]open up the MO FO...then deal with how smooth the air flows...$.02