I'm looking for someone with experience removing the lower plenum section. I ask because I want to get to the electrical harness plugs of the individual injectors and I think I'll need to remove the lower plenum to reach them. Ultimately I want to verify that my N20 system is properly wired to the injectors.

 

I have removed it. Its no problem at all. Just remove the bolts holding the center plate between the intake runners, then the 2 nuts external (front and rear). There are a few hoses and a clamp that have to be taken off as well. The gasket between the last intake runner and the lower plenum is pretty tough with no sealant on it so I wouldnt worry about needing a new one. Depending on mileage, you might as well change the spark plugs too. They are right there. I painted my upper and lower plenum while off too. When reinstalling, make sure not to overtighten the bolts. The aluminum threads can strip easily. Have fun.