The less nails the better for on road actually... besides, DF03 replacement tires aren't expensive at all... so you guys can get 2 sets, one for onroad and one for offroad!!! That's how they play in Tamiya Buggy Cup!!!
The metal damper is a must buy item. It absorbs better and its cylinder is longer than the plastic one. Fine finishing. Good looking too. The metal damper is totally worth it.