The video for connecting the HBridge is all you'll need :)

Do I need to buy this Motor Controller? http://www.robotshop.com/dagu-wild-thumper-dual-15a-motor-robot-controller.html

No, I don't know anything about that Microcontroller. EZ-Robot has our own Microcontroller (EZ-B), and add-on hardware. The HBridge in our store has a video that demonstrates how to connect motors to it :D

Since the Thumper is 4wd, will EZ-Hbridge still work?

how to conect 2 h bridges to ez robot because: 4WD version of Wild Thumper is an ideal platform for your EZ-Robot. The aluminium arm gripper compliments the chassis beautifully. 4 powerful motors and an adjustable independent suspension system lets little chassis go almost anywhere. Comes standard with motors, wheels, gripper and servos. *Note: Requires 2 x 2.5 Amp Motor Controllers from our store (One controller for each set of motors).

Can someone send me a wiring diagram for the 2 x 2.5 Motor controllers,

Thanks

confused

I am also interested in this though I am assuming that the inputs are simply connected in parallel. Then again, assumption is the mother of all f**kups... would appreciate a reply on this subject.

Given the amount of power the thumper needs you want to use one h bridge for the front and one for the rear. Many use a 3S lipo battery which is 11.1 volts at the minimum. The inputs on the h bridge you parralel to the same inputs on the second h bridge.