Personally i think people are looking waaaaay to deep into this, of course bar Nismoid.
So what exactly is lowering the intake temp 7'C at idle going to achieve in a street driven car? A .000000001 second decrease in time to the next set of traffic lights?
Im with Nismoid. Unless its a fully blown race car where every single bit of HP counts, its a waste of time.
(that and of course if the OEM gasket was a similar price, then why not..)
And also to add to what Nismoid said about the IC sprayer, theres a good test on them somewhere online where an Aussie guy did intake temp readings on a car. The amount of full throttle boosting you need to see and increase in intake temp on the street is phenomonal. Like, 20 seconds plus. And if in 13.5 seconds, a quick GTSt can reach 160-170km/h, how quick are you really gonna go?
And with the sprayer. The car needs to be moving slow enough for the water to cool and absorb some heat from the IC core before your on the throttle again, or its just squirting water for no reason. Hence why when in "Auto" mode, Evo sprayers only spray when the brake pedals pushed. Holding the sprayer down on the back straight is doing absolutely nothing. And if you do it on the drag strip, you should be shot.