First of all, if you get the XXX KE you better get rid of those disgusting blue wheels first thing. I cannot stand those ugly things. Brian Kinwald was at my track this weekend and he didn't even use those faggy blue things most of the time. He just used them in his first race and went on to the yellow ones.
The Dually is a great choice for an ESC (that's what I use), but I wouldn't stop looking just yet. It works flawlessly, but it is quite big. Be sure to look at what LRP, Futaba (they actually make nice ones now), and Keyence have to offer. I would go for one that is a bit smaller if you could. The Novak C2 is awesome and not too big, but it is very expensive. I dunno...look around and see what you like.
DEFINITELY go with 2400 battery packs. They are the best all around IMO.
Motor-wise, you have to be careful. Although a Trinity GM3 might be better off in a buggy instead of a truck, I STILL wouldn't get one. They are just too iffy and can die on you at any time. What a pain. I've already toasted two in a month, and I'll NEVER get another. You can't go wrong with a Trinity P2K; they are the strongest stock motors out there. Also consider the Reedy MVP and Orion Chrome Stock/Peak Spitfire. Weigh the pros and cons and decide what you like best. Just don't take a big chance on a GM3.
If I were you, I wouldn't waste my time and money on the archaic design of the old Airtronics CX2P. I'm going to suggest the best deal out there for a radio. I got my Multiplex AM/FM Profi Car 403 radio for only $160. Go <a href="http://www.multiplexrc.com/tx_profi_car.htm">here</a> to see what I'm talking about. Read all the info and you'll see how cool a radio it is. I love mine.