I don't own a Gen 5 or know the engine bay layout at all, so this is is a generic set of comments.
1. Most aftermarket so-called "cold air intakes" are just pod filters in the engine bay replacing the factory air box. Some might put the filter in the guard, some might have some attempt at sealing the pod filter from hot engine bay air (not usually a good seal). Do you due diligence and use your brains before buying anything.
2. Drawing in hot engine bay air is bad for power due to reduced density and knock risk. The computer will pull timing to account for the increased knock risk of hot air. An intercooler cannot "mop-up" after an engine bay pod filter.
3. If the factory airbox has a reasonable source of air ducted from outside the car, that might be left alone, or perhaps mildly improved (sealed, de-burred, heat-insulated, whatever).
4. The factory airbox often has a hole in the bottom for a big plastic resonator. This is an opportunity to add a secondary feed to the factory airbox like I did (
viewtopic.php?f=10&t=36234&start=15 ). See the details in the thread, but it's a problem-solving exercise running the right sized silicone, aluminium or convoluted hose from the airbox to a reliable pickup point for cold air, ideally forward-facing for a mild ram-air effect. Convoluted hose will be the easiest way to route the incoming air through a complex series of bends. My alloy & silicone solution produced a box of unused pipe & hose sections until I got the combination right.
See also the plentiful articles on the Autospeed website for these types of projects.
5. Nay-sayers will warn you about ingesting water through the pickup point. I've been running this setup for a while. I did something similar for a VR commodore I used to own. The worst thing that ever happened with water was a saturated air filter (and reduced power) in the Commodore one night after driving on the freeway in torrential rain. No water was on the clean side of the air filter.
Enjoy the project.