Interesting subject, not to compare how good on different gearbox existing in the market,
I only talk about our PDSGB, yes, Sollie and Longsheep said, the gearbox original design for HL type lower hulls, included Taigen, Torro also can direct fit in.
and the very nice feature to let you switch the gearbox to different tank very easily.

Why we don't make it compatible for Tamiya tanks, because only Type-10 and Leopard2 electronic support this gearbox, all Tamiya WWII models cannot directly use this one since DMD not support, and I don't think they will throw away the new DMD and MF to get this gearbox in. unless they really want to do that, For Tamiya tank, we make a brace plate that support Leopard 1A4 and Gerpard since no electronic come with these kits. people has some choice on that.

if someone really want the PDSGB fit their WWII Tamiya tanks, contact me via FB message or drop me a email.
I will try my best to help.

Cheers,

Carson L