Thanks for all the recommendations guys. I really appreciate it.
BrianG - You mentioned the gearing 44/17...? Where can I get a 44t spur?
jhautz - About the 4s 3000mAH battery, I haven't heard great things about the 6000mAH packs. So would it still be all right to run it? It won't heat up too much under heavy driving? Now I have the option of 1 4s 4000mAH pack ($150) or 2 4s 3000mAH packs ($220 for both)....
What weight oil are you all running in the diffs? I will be driving on a variety of surfaces (asphalt, pavement, sand, gravel, grass, etc.) and would rather not change the oil every time I drive.
Edit: Just noticed the tires you're running jhautz. Are those the stock rims with the Traxxas Anaconda tires? I was looking to pick up a set of street treads.

Do they fit perfectly?