UGV Monster truck platform

I'm planning to build a UGV monster truck, based on a Tamiya Super Clodbuster. I've heard that it's a lot cheaper if you buy it in pieces. However, I ran into a bit of a dilemma. The stock monster truck comes with a speed controller. Do I need that too (I don't need any RC functions) or can a motor controller for Arduino or Basic Stamp do the job too. I already own a BS2 with BoE, but I would like to buy an Arduino because it's cheaper, open-source etc. Note: I'm still a beginner in robotics.

What do you recommend for me (hardware)? Do I need that speed controller? Any recommendations?

Please reply!

Thanks for help!