Xbee question?!?

Hi!

I just purchased two of the Xbee Pro 900 XSC s3b modems. What I failed to realize when before I configured them is that they do not support API firmware.

I am planning to use them to communicate with a robot; I'll be sending data about the button states and stick position of a ps2 controller to the robot and sensor data
back to the "base station" arduino board.

Is this practical using solely AT mode or should I purchase another model that supports API mode for my project? I am new to wireless communication and greatly appreciate any advice I receive.

Thanks!!

Walter