The Wilson 5000 is an overkill, though it would work too. Unless you're going to run 3000 watts and then why would you want/need a mag mount anyways?
the 1000 and 5000 have the same performance just the 5000 will handle more power and if your planning on running enough power to need the 5000 like Turbo-T said you dont want to be running a magnet mount antenna anyway