I have the TJM Airtec Snorkel on mine working with the factory airbox. I was able to make everything work with that snorkel. The one problem that can result from the Airtec is the lack of air flow that you require with a snorkel. If you compare the Airflow to the Airtec you will see that the mouth on the airflow is much larger than the Airtec. The basic tubing of the snorkel is relatively the same except with the Airflow its a straight shot for the most to the intake tube with only one 90 degree bend in it where as the Airtec has three 90 degree bends (not as direct).
A fix that I have been looking at doing is swapping out the intake mouth on the snorkel for a Land Rover style pre cleaner. they are only about 50 bucks or less to replace. For the installation portion of the snorkel, the Airtec comes with a disgram you can tape on to your fender and drill holes with, I wanna say its 7 14mm holes and the giant 86mm hole for the main tube. It does not come with the A-Pillar diagram, you will have to figure that out on your own. I removed my weather stripping and cut the hard plastic around the windshield as well as the weaher stripping around the mount. There will be two screws that go in to the A-Pillar and i believe are either 4mm or 6mm hole. There is a giant hole in the factory air box that was meant for one of baffles, you will need to plug that. I used a thick piece of Plexi-glass and drilled a few holes in it for screws to hold it in place and then sealed it up.
Another thing I had to do was take the factory "T-Pipe" as it is commonly referred too, and dremel out the inside as well as cut off the bend on it. This can be hard to do because if you cut too much off you will be going to nissan to buy a new one. After your take some of the inside of the T-Pipe off you have strech the hose around the intermediate pipe on the snorkel and make sure to seal it all up with some heat resistant silicone. Ive had mine for close to 3 years and not had a problem. If youd like and when i get some free time i can take pictures of all of this stuff and post up.