And just a hunch, but most of the time, a CAI has very little effect on engine power. Sometimes the CAI can actually increase intake temperature because the open-air filter is getting more hot air from the bay, because there's nothing to shield it from the engine. That's why I'd be more interested in making a VX-proto-style hood vent, since it will help cool the engine bay. I'm not saying it won't work at all, but the only way to factually determine efficacy of a CAI is to have a digital temp readout on the filter.

Even still though, bear in mind that if you have a hot bay, the air flow has to make it up to the manifold, and will get heated along the way. That's the biggest reason for having a vent. You can put scoops on, but they won't help to bleed the hot air, and scoops really only help with ram-air in a sealed system.