I have this antenna installed on my truck and it works great for gps and wireless.
I used an Axiom GPS module inside my case with this antenna.
http://www.allsurplus.net/Axiom/
No cell phone so haven't tested that part yet.
Install does mean drilling a 3/4" hole in the roof, but this is a standard roof mount antenna size - so just about any decent install shop has a shallow antenna holesaw just for this purpose.
Once the hole is drilled, drop the wires through and bolt up from underneath.
Then you just get pigtails from FME-male to whatever your equipment has.