I have a Tamiya Tiger II. The plastic tracks and the idler are the weak points to the running gear. I replaced the plastic tracks with Kenny Kong metal tracks and modified my idler adjustment with stronger springs and that fixed the issues I had. At some point I may replace the idlers with Darryl's upgrade or use the the Hentec upgrade. I have not added a gearbox brace upgrade to it. I am still using the original gearboxes. The kit is about 6 years old so I think I have gotten my money out of the original gearboxes. Now all that said I do not run this tank like a race car. I go for a more scale speed. If I were to battle it like they do at Danville I would have to add that gearbox brace or at least reinforce the lower hull to keep it from flexing and would definitely replace the gear boxes. Just look at the videos they post of Danville battles, the tanks are moving all over the place like race cars. Not a knock on the battle speeds just making it clear that if one is just driving at scale speeds the Tiger II may be ok with stock parts.I do agree with Ausf about the metal barrels changing the longevity of the plastic elevation arms.I used the plastic barrel on my King Tiger and it is still going strong. Same for my Tiger I as well.