My snorkel was really easy and cheap to build ($110 CAN or about $70 US ). For '84 - '96 XJ's, You DO NOT need to remove the fender. For '97 and newer XJ's, you will need to remove the stock waser bottle and replace it with a pre '97 unit.
I'll post some pics and info here. My setup is almost exactly the same as ARB's. Here is a Pic of the ARB routing.
First you decide where you want everything to line up. Go to you local hardware store (I got mine at Home Depot)and buy the abs parts you will need. Here is what I used:
Parts:
1 - 4' length of 2" ABS tube
2 - 45 degree elbows (both with female ends)
2 - 90 degree elbows (both with 1 male and 1 female end)
1 - 2" coupler
1 - 2" to 1 1/2" reducer
1 - 2" shop vac hose (I used Rigid from Home Depot)
2 - 2" hose clamps
silcone
1 strip of door edge guard
2 90 degree brackets to hold pipe to body(I used Stanley chair leg braces from Home Depot)
Tools:
Drill
2" hole saw
various drill bits
Dremmel Tool
Decide where you're going to cut your hole (look behind the fender to make sure it's clear on the other side) and cut away! This is the scariest part. Use a dremmel to clean up the hole and make it larger if nessiccary. Take your door edge guard and install it on the edge of the hole (use some paint on the bare metal first to prevent rusting) Once you've cut the fender move to the airbox, remove the cover and filter and drill a 2" between the bolts that hold it in place. (check below to make sure you don't hit anything else).
This is what it will look like under the airbox(the original hole is where to drill for an ARB snorlkle, it's not from my jeep).You'll want the hole where the red line is.
Once you have your hole drilled in the airbox (thru the plastic and the metal) you need to remove the air box. Cut off the factory inlet and seal it (I used some plastic from the side of the old intake and siliconed it to the airbox). Then take your reducer and silicone it in the hole. Let that dry over night.
Now you can start to cut your ABS pipe to fit (it's not rocket science here kiddies). Paint it and let it dry over night. Take your 90's and join them thru the fender.
Join all your pipe and elbows until you have it where you want it and attatch it to the body using your 90 degree brackets. This is what I used:
As for the top (intake) you could use an 90 degree elbow. (this will keep the cost down to 20 bucks) I bought an ARB intake for $90 CAN to give it that "finished look". If you do the same, you'll use a 45 at the top of the pipe and a 2" coupler because the ARB intake is designed for a 3" pipe.
Back to the airbox, reinstall the airbox and attach the shop vac hose using your hose clamp. If it doesn't quite fit, you can heat up the hose and stretch it slightly to fit. Now just route it thru the fender up to your 90 and attach it with your hose clamp. You may have to use some zip ties to hold the hose in place.
Once everything is in place you should take the ABS pipe apart and glue it with ABS glue for a nice waterproof seal. Here is what the finished product should look like. Good luck! By the way, I have build 3 of these now and they have all turned out exactly the same. It's very easy to do.