The Tamiya gearboxes will outlast Heng Long stock metal transmission unit gearboxes hands down. When protected from dirt and dust by a cover and properly lubricated with routine cleaning, they will last for many years w/o rebuilding. The HL are not as very precise or durable. Some are very noisy and junk brand new. What they are without a doubt is cheap and effective. They do need to be tuned and require a break-in period. Quality control with HL is still hit and miss. These problems are what made room for Asiatam and Mato to introduce their our HL TU variants. I myself use Tamiya, HL and Impact (3:1s in my Jagdtigers for their very slow speeds) in my dozen or so IR battle tanks. The final or output shafts as mention by my fellow NEAD members, are different for Tamiya and HL. Depending on the application you could customize them or buy the Tamiya drive sprockets. Just remember that all Tamiya and HL tracks are NOT fully interchangeable. If you let me know what you want to do I may be able to help you out with compatablility issues. We all try to get the biggest bang for our buck and the HL metal TU is a viable choice for the costs. There are three main types of HL TUs: stock plastic (cheap), HL stock metal (the Chevy version) and aftermarket HL full high quality metal (Caddilac version). And then there is the Atiatam (very good and highly reccomended) or Mato (brass version which I don't recommend) aftermarket versions.

I hope this answers your questions...... Bob, NEAD CO