Because of where the antenna is located on the drivers side forward roof pillar I would assume that you would have to get creative on where to mount it. if I was doing a 4 ft firestik I would make a mount that comes off the spare tire rack and is abut 3" above the spare. Running the antenna cable would be fun.
If putting a shark fin on the roof, you would definitely have to get creative. Probably would require removing the headliner.