That Jeep link is OK, but you can tell they don't really know what they're doing.
Here is some tips for installing roof mount antennas:
-Pull the headliner and locate braces, HVAC ducts, wiring harnesses, etc BEFORE you drill any holes. You don't need to pull the whole thing down, just enough to get a good look at what's between it and the roof. Always know what is under the hole you are planning to drill.
-Use a tape measure or yard stick to get the holes centered and spaced evenly. You only get one chance to the drill the hole, make sure it's where you want it.
-I know this is a shameless plug, but you really should use a good quality NMO hole saw like the
Antenex HS34. It is depth-limited to prevent cutting through the headliner when the saw breaks through the roof. It also has a pilot bit to keep it centered exactly where you want it. Using a plumber/electrician type hole saw is just asking for mangled headliner
-You don't need to push the mount up from the bottom like the people on the Jeep page did. The NMO mount is designed to be installed from on top of the roof. Just drill your hole and feed the coax and mount in to it. Then secure it with the outer locking ring.
-The slugs from drilling the holes will be HOT, and I mean HOT. They will easily melt a headliner. You should put something like a pie tin or similar non-flammable object under the hole to catch the slug.
-TAKE YOUR TIME. You might as well spend the time to do it right rather than try to fix it later. Don't have the "there's never time to do it right, but there's always time to do it again" attitude.
People make a big deal about drilling holes in their cars. Personally, I think it's the only way to go if you are serious about having a quality radio setup. FYI, I recently traded in my 1997 Dodge pickup with a bunch of holes in the roof, it didn't affect the trade-in value a bit.
Here is the roof of my 2004 Durango that I recently outfitted. As you can see, I'm not shy about drilling a few holes in a $35,000 vehicle before the first payment is even made!
That's all I can think of right now while I'm eating lunch. Let me know if you have any questions. Oh, and be sure to check out
http://shop.waltel.com for everything you need for a quality installation.
Jeff