Obviously, with so many parts on the market, it's difficult to decide which is best, and taking the word of someone you don't really know can be risky. My recommendations are also provided to you with the understanding that there may be equipment out there that better meets your needs/wants. These recommendations and links will give you a rough idea of what's out there. They also assume that you are trying not to spend the highest amount of money, but get good equipment (value). Use this guide as a generic reference to what's out there and what to upgrade on your E-Maxx. Note: the links are there for a reference only, and the equipment may be available for a lower cost, faster shipping, or with better customer service elsewhere.
(in no particular order):
Great Assembly 2 and 3mm titanium (3mm is very heavy, but virtually indestructible)
Suspension:
Too many to list, but I like the Maximizer beadlocks because no glue note: the plastic beadlocks are pretty heavy for wheels.
Shocks:
Steering servo skid plate:
Chassis: (optional)
Again, there are so many, you should decide your need to settle on a chassis. The stock tub works fine for most intents and purposes. Then there is the new kit from Bomb-Proof Products called the Torpedo and Race Bomb lexan chassis, a nice one from GorillaMaxx, the inexpensive aluminum plate from New Era Models, the quad (battery packs) from Dynamite, and the very fancy polished aluminum chassis from Unlimited Engineering, along with many others.
40-80wt shock oil (depending on your preference and weight of truck and hardness of shock spring)
Wire (optional):
The best I have found is the Deans "Wet Noodle"
Connectors (optional):
Custom and special stuff (optional): www.rcalloys.com has provided us with the strongest and best looking drive shafts known to man, and took the time and effort to fabricate, from scratch, a very strong and rare spur gear for my dual brushless E-Maxx. Consider contacting them to see if possibilities for your "special" ideas exist for fruition. Their standard products are absolutely of the finest possible quality. If you're in the market for strong and gorgeous wheels, skids, and anything else you see there, check out their site for those options.
for a great full kit that includes many of the recommended parts, check out Great Assembly's SM/GA kit including RockHoundz or GA titanium skid plates!