[IKE]

If you plan to go that route, look around for discussions on "driving straight". Typically the "zero turn" style drives are diffi ult to drive fast and straight. If you are not driving the front wheels, using the 2009 hard plastic wheels on carpet may be a good choice as well. They are very slick, but predictable on carpet so you do not get the caster wheel shift when changing directions.
Overall, this configuration tends to be limited for FRC. Having non powered wheels puts you at a disadvantage in a pushing match or if you need to stand your ground. The lack of naturally going straight makes many autonomous routines more difficult.