I think only specialists will have access to the last driver class that makes it less expensive to repair and allows you to use black/red and other M.A.U.s I didn't play for a while so this might not be correct, but I think that's how it is...

Being a ranger doesn't help at all in being a ranged MAU. MAUs have different stats from your character, they depend on what they're made of and it all depends on your driving level, your class only affects what you're like outside of the MAU but as far as I know, the one that excells in MAU driving are the specialists.(in PVP sometimes you will have to switch Maus and there your defense will probably be more important than your ranger abilities, so it might be a good idea to lvlup blocking too)