I found THIS THREAD a couple weeks ago when poking around before I got my truck. Looks real clean & simple, although PVC is not advisable to use in the engine compartment due to a toxic gas it gives off when heated. Plus, it also softens up when it gets hot. I think the black ABS pipe would be more appropriate if you were to build something like this. His design looks great, but material choice isn't the best (granted, there's not much choice in materials when sourcing materials from HD or Lowe's).
PVC is alright to use for intake, people tend to over react a little with things like this. PVC is designed to handle temperatures well beyond 115 deg F degrees, which the intake is usually right around that temperature. CPVC for home water lines has to handle hot water from the water heater(120 deg F or higher), and regular pvc is much stronger. It takes A LOT of heat to distort pvc and emit gasses, trust me I've used a 1200 deg F heat gun to bend pvc and it took about 5 minutes of direct application before it started distorting.