I did it. If you don't have coolant lines inder the plenum, you don't have coolant lines to repair under the plenum. If you are in Canada and drive year-round, keep those lines. If you are in a warmer area, get rid of them.
The coolant heats the T-bodies ( to stop possible sticking or freezing in really cold weather), therefore the incoming air is heated as well. Which is counterproductive to our goal of cooling the incoming air with bigger intercoolers, cold air intakes, etc. to make more power.
I am doing the same next month (swapping in a powder coated plenum & TB's)
I have already eliminated the water pipes from the powder coated TB's and will also be eliminating the EGR system and it's associated vacuum lines.
This not only does away with numerous lines, and their possibility in the future of being a source of leaks, but also makes removal of the plenum easier since (including the water lines to the TB's) you can simply cut them to remove the plenum
"Eventually the EGR valve itself gets all gummed up or carbonated to a point where it will leak to some degree no-matter-what, so if you have the opportunity to ditch it, ditch it and pat yourself on the back. "
Also, none of the ECU upgrade chips currently address the EGR anyway...
Plus, it will clean up the engine bay quite a bit as well.