Originally Posted by Jordo!

What's running hot? Coolant? Air intake? Oil?

How hot is hot?

If we're talking a 10-15* change, especially at idle, you might get away with just venting, but really, you'd want to have air ducted to an actual heat exchanger, and not just a place to allow ambient heat to escape. For example, typically with a top mount IC, the heat changer is mounted close to the hood, so you will commonly see a large duct to allow air to pass over the heat exhanger -- it's not simply designed to vent off ambient heat (although I believe a few older Camaros used to have a backwards facing scoop for venting...).

Also, pure ductwork venting/cooling is trickier to get right than you might think -- if you are in a low pressure area on the car, the air might not flow where you had intended.

Meaning, I think you should not bother with the hood and instead identify which heat exchanger is insufficient and replace that.

On that note, if you are using an A2A intercooler, you might consider switching to A2W. Then you can mount the heat exchanger wherever you want, duct accordingly and take advantage of the considerable heat absorption of water.

Another option is to have a water spray set-up or use water/alcohol injection, which will also absorb tons of heat.