I really don't think it's that much of a concern. I haven't looked at detail under my hood yet, so I can't say for sure if there is coolant running through the TB or not. Either way, I would leave it though.
The main reason that the coolant is there (if it is in these cars), is to prevent the throttle from freezing in cold temps. The high velocity air going through the throttle cools it off below ambient temps, and can quickly freeze over in colder temps. This is commonly looked at as a terribly hinderance to performance, just like EGR.... although it really doesn't hurt much at all. In the short amount of time that the the air touches that TB at WOT, it doesn't even have a chance of heating up enough to make a difference.
In the end, if you live in a cold climate, you'd better leave it in there, of suffer the stuck butterflies. If you live in a warm climate where it never drops below freezing, I seriously doubt that you'd ever notice a difference once it's removed. Don't bother.....