The "search" feature is your friend! If your tank comes with metal gearboxes, take them out and break them in properly as per the FAQ. If your new tank comes with metal suspension mounts and screwed rather then pressed axles for the wheels you probably won't need the metal suspension arms. Metal tracks are cool and essential on a Tiger if you plan to run it outdoors on any rough terrain. The track links will break just like a real one.

If after a couple of hours of use you find that this hobby is for you, throw away the battery and buy a 3000+mah battery and peak charger, there's some good deals on 4200s and buy 2 while you're at it, one for you other tank. What other tank? No adult tanker owns 1 tank.

The newer tanks electronics are more reliable, that doesn't mean that things won't fail or break. It's always a great idea to have spare parts on hand to make repairs, crystals, boards, radio, smokers, etc. The smokers are a PITA and don't last. Plenty of posts on how to fix them. Again, the newer ones are better though.

Read through this and other tank forums, look at the builds to see what can be done with these machines. It's addicting and a lot of fun.