As an engineer you can drive the support vehicle (same size as a humvee/jeep)
request a crewman kit to drive a tank or apc. There are rules for requesting kits and rules for tagging a vehicle in the manual I hope
request a pilots kit for choppers and planes
requesting kits relies on being in a squad and a certain number of players in the squad and you joined/made the squad before the round countdown timer or have been in the squad for so long.
Rnaks aren't a major issue. The ABR system of Alternative Battle Ranking applies to a lot of PR servers (current issues with making ABR run right under certain specific circumstances)
Ranking does provide some self respect I guess (says the man who got a few badges he'd missed and suddenly hit Colonel

)

[R-MOD]Mongolian Dude: AH man, sarcasm is so hard to get across the web, even if we are both british
[R-DEV]Jaymz: That has to be...the most epic response to a welcome thread I have ever seen. [R-CON]Mr.D ladies and gentlemen!