I'm not too sure. I still have the Hondata one on my Integra and I think the gains are minimal at best. One thing it does provide is a reusable gasket versus the stock paper ones which need to be replaced every time the intake manifold is taken off (on the Integra).
To be honest with you, I'm not sure about the temp thing, either. There is data on the 55K motors that shows the heat doesn't come through as fast, just because metal displaces heat better. In my mind, it all equilibrates over time, so I'm not sure what they do.
The part they do help is in increasing the volume, though. That is where I really think the bump comes from.
I'd be curious to know if teh RennTech box will fit with them on. VRUS had to re-engineer his to fit with them on, since nothing in the box flexes.