I had a good sit down rag chew with my elmer about antenna mounts. I was going to put my mobile in the truck and was having a hard time with the selection of a location. I didn't know at the time anything about a ground plane. After we went over the benefit of a good location I did drill on the cab. Pulled the rear light on the cab and drilled as far forward as I could reach to get the nmo installed.. Three years later I picked up "Barbie Car", or that is what my wife calls it.. Ford fiesta for the gas mileage, installed a trunk mount on the back left
Nmo mount and it works real good. But I am using the super gainer antenna on the car. The truck antenna has 3db gain on 2m, the car has 5db gain in 2m. I was expecting the car to do better but it doesn't. I spent an hour drilling bonding straps on the car trunk panels to frame but it still is not as good as the truck. It definitely favors certain directions based on the location I mounted it. However I dont have to worry about folding it over if I drive under low covering.. If you have good coverage in your area and not pushing the edges the low mount would be fine.. If you need every mile you can get, go up top.. The mounts are getting better, some people make their own... If you go strong enoug you can use it for hf mobile.. Good Luck...
Prosise