The option for ABS is for the previous Replicator 1, and Replicator 2X.
ABS is a bitch to work with. Makerbot is making as many moves as they can towards something that's a consumer appliance. And if PLA can help them get there with an 80% use case coverage, so be it that you can't print parts you can leave in your car.
That's not a good thing - that means you can't really print functional parts with this, only demos.
PLA has too low of a glass transition temperature, so parts will deform if you leave them in a car, or outdoors in the sun in the summer.
Plus it starts to degrade if exposed to temperatures of around 100F especially if in a humid environment, giving it a limited lifetime.
i.e. if you want to use this to print parts for your car or your computer you can't.