Wing mount
Bearings (wheel, clutch)
Servo (backup)<-----trust me, this will end a race day!
Hinge pins
Screws, nuts
Rod ends
Those are some good things to have extra. Its good to have extra parts, if you got the money. But I just wouldn't go overboard right away. I bought a whole set of brand new a-arms for my buggy when I got it and I haven't even used them. I would just see what commonly breaks alot and buy extra of that part. And when you buy spare parts, also look into upgrading while your at it. Like when I kept breaking my wing mount, I went and got a Tekno wing mount and it has yet to break. Even if I do break it, it has a lifetime warranty so I can get it replaced at no charge! So you cant go wrong there. And its like $25, but the last wing mount you will have to buy....
