This is a really cool product. Get it? "Cool". Ha!
Anyhow...the Randall intake replaces the snorkel from your stock airbox with a carbon fibre tube that gets cool air from the high pressure area in front of the windshield. Cold air is dense air, which means more power for you. Most intakes are dyno tested with the hood open, so they perform at their best. As soon as you close the hood, the intake temperature shoots up and all the power gains go away. Not the Randall - in our testing, we saw a solid 5 hp gain with the hood closed. You'll also get a bit more intake growl under load.
Installation involves cutting a hole in the flange at the top of your windshield, above the firewall. This may not be allowed in some race classes, so do your homework. 1.25" holesaw required, not included.
Fits all NAs with left hand drive. Sorry, it doesn't fit with right hand drive.
Dyno proof! These runs were done on the same car back to back. The blue run is the bone stock car with the hood closed and the usual fan blowing in the nose. Red is the exact same situation, only with the Randall installed. The green dyno was us goofing around, we held a fan near the base of the windshield to simulate a "ram air" effect. As you can see, even without the handheld fan it's a very worthwhile upgrade.