Thinkin of gettin one for my RPM II. Are these really worth it? Any real gains with these? Does it keep the upper intake cooler?


Upper will be cooler as a result of using a spacer. Also, the extra 3/8" or 1/2" will aid torque due to a longer intake runner. This is what I understand. You can search for before/after results on an install, for the gains. It all adds up.
I have one on my factory intake w/no broken tab issues. If you remove/reinstall upper, make sure you don't over-torque bolts. Not saying this is definately why tabs break, but you've got to be cautious about this. Aluminum is pretty soft and doesn't take much to crack or split it.
Anyway, the intake can further be cooled by not using the coolant lines routing to the egr spacer.
Mike
Only if you also block off the egr passages at the lower intake or the head.
Also the longer runner brings the powerband lower in the rpms. You get more power down low, less power up top. It's a tradeoff but it can help heavier cars get going a little quicker, they'll be slower on the big end though.