This is a link I dug up last year when I was researching the install. It helped my a lot and saved a lot of
Your going to need a Dremmel with a 90 degree head on it with a cut wheel. The battery tray supports have a hole that need to be enlarged. (Directions failed to mention this, luckily I researched before I started the install) That is the only really hard part. I don't have any pics handy of the airbox mod but it is easy to do. You just twist off the stock "snout" and ARB gives you a plate that you pop rivet to the box. Make sure you buy some caulk or RTV to seal up the plate. Then you have to cut a hole in the side of the box, I again used my Dremmel for this. Then you put a bead of caulk/rtv down and pop rivet the new plate to the box. This plate has a metal tube protrudine back and slightly down that you fit the flexible plastic conduit over. This affixes by means of a pipe/hose clamp. The directions don't say this but I thought it was a good idea to throw a bead of caulk all around where the pipe and hose connection. The hose fastens to the snorkel in the same manner, I also used a bead of caulk on this. If you don't seal it up good your going to suck water into your engine and hydro lock. You have essentially lowered part of your intake system by over a couple of feet making your engine more vulnerable to hydro lock, that is if you didn't do a good job. Your also going to need a hole saw, buy a new one. It will make your job a bit easier. As for cutting into the side of your Jeep measure several times, cut once. I did that and still didn't get all of the holes lined up right.
I had np with the 3" or 3 1/2" hole, can't remember. But the large hole has a smaller hole above and below it that you feed two studs through to stabilize the snorkel. These holes did not line up. They were a whole hole diameter off, so I had to re-drill. I have to oblong holes now, but I wasn't stressing it because the snorkel covered up the area. Make sure to hit up any areas you drilled with a rattle can. It really doesnt' matter what color paint you use as the area is going to be covered up. Oh, and ARB does provide a drilling template to be used, I think the guy that made mine was asleep at the press because I followed it exactly, oh well. Oh, I have AC as well and this is what I had to do, I'm not familier with what a Jeep without AC is required to do to their airbox? One thing to consider is if you ever plan on going with an onboard air system like Kilby. The area you install the compressor is the same area used by the hose on the side of the airbox. You could probably make something work though. It would just take a bit of creativeness.