For 15 months of racing (17.5T,10.5T Turbo modes), this shaft is a must for me. Strangely but true, it improve traction to rear F1 tyres due to its weigh. But more importantly, I can use 1/12 Gears with 16 ceramic balls which is very efficient, smooth and low maintenance. And because of no need to use Tamiya 104 original alloy centre diff part (silver part), as this TRG gives the same Steel structure instead, the whole Diff assembly is much stronger against accident and effectively provides protection to the Tamiya diff's out sleeve (blue diff casing) which sometimes bents. It's extra weight is worth it.