I built mine out of some PVC pipe a rubber elbow and some other misc. parts found at any hardware store. I first capped off the stock inlet to the air box. Silicone sealant or similar is a good idea to prevent water from getting in.

Next I decided where to cut into the firewall and cowl. I ran 2" pipe from the box up to the rubber elbow, where I stepped up to 3". The connection to the box was achieved by using one of those PVC 'compression type fitting'. I removed the compression ring, and used the screw on part to clamp the side of the box in tightly. The whole thing was sealed with silicone inside and out.

Once I had the rubber elbow coming through the cowl, I needed to make the 'stack'. Two pieces of 3" tubing (3' all together will be enough) will make the most of the stack. One piece between 8 and 12" long will run horizontal along the cowl, behind the hood line. Attach this to a 90° elbow to turn the corner up the windshield. Another section of pipe (approx. 20" long) will follow the contour of the windshield up into a 45° elbow. This is make the inlet of the snorkel be parallel to the ground. I found a half-round 'mushroom cap' in the vent and flashing section, I used this to cap the inlet to keep the rainwater out.

Two pieces of sheet metal, or plumber's strapping can be used to secure the snorkel to the a-pillar. This is an important step, without doing this, the snorkel has no support and will fall off or break!!

Using PVC glue at all the joints is recommended, so that the pipes don't separate, as well as for waterproofing. I used that cheap undercoating in a can to coat the stack, but it will crack and fade out in the sun. So I suggest using something like flat black paint or something like that if you don't want the tube to remain white.

Also, be sure to position the upright tube so that it blocks a minimum amount of vision, as this can greatly increase your blind spot at the passenger side a-pillar.-TRS