A year ago I completely insulated the intake on my 03, 5.9 Dakota. Since the daks aren't plumbed into the fender well, I removed the convolute that was attached to the air cleaner housing and plumed right into the fender well (like most trucks!). But I do wonder if it was a waste of time since the components of the intake system probably end up the same temp as the engine compartment because of the radiant heat absorption through the inso. On a side note, interesting thing about the direct line to the fender well is that the air cleaners never seem to get dirty, although I continue to replace every 15,000!