Interesting...
The colder air 'leaving' the intercooler is definately 'slower', kinetically, than the air traveling from turbo to intercooler. As such the shortest pipe needs to be the interccoler to plenum one. It is therfore at least being 'slowed' at an atomic level' as heat energy is taken out/lost from the system.
I am not sure if the same principle can be applied to intercoolers but, in an exhaust situation, thermal shielding adn trapping the heat engery in the pipe increases substancially the speed of the exhaust gas exiting the engine.
the paradox would be that hot air is faster to get from 'a' to 'b' and yet cold air is better for combustion.
At some point there is less benifit from a colder intake charge then there is from keeping the air speed up.
Don't know if this is right but, someone want to comment?