I added an SVT snorkel to a stock air box a few weeks ago, unfortunately I do not have a digital camera so no pictures. It is a great and cheap mod.
1. First removed the air box then switch out the stock snorkel for the SVT.
2. Then hold the box over the stock mounts to see what needs to be cut away to make it fit. You should find that a 1"x1"piece of the stock sleeve nearest to the valve cover can be saved as well as a 1"x1" piece that would nearly be parallel with firewall. The pieces that were saved are used to help hold the snorkel in place. Just use a saw zall or a hack saw to cut away the rest of it. I used a bench vice to hold the box when I was hacking and slaying on it.
3. Once again place the box over the mounting points, and use a pencil to mark where you need to cut away the rest of the opening.
4. When you are able to slide the box over the snorkel and into the stock mounts, use a screw clip or two on the end of the snorkel and run a screw or two ran from the inside of the snorkel out, that way it will not interfere with air flow.
5. Use some good silly-cone to seal the snorkel to the box.
Steps 2&3 may need to be repeated many times if you want a close fit, like I did. I think I spent somewhere around 2-2.5 hours working on it, but I was in no hurry. Let the car sit over night with the top of the box off to help cure the silly-cone.