It still remains that I have no appreciable difference in power or economy. Its arguable that I actually have more power without it since pumping losses from pipe bends and the intercooler core are eliminated. (Thats another reason I'm going air/water on my 300D.)

Diesels only care about having at least enough air to burn all the fuel, charge temperature just affects how long the power can be maintained safely.
G@ssers are different, a few degrees difference in charge air can make 10+hp since an A/F ratio must be maintained and more/less mixture can get into the cylinder.