Rob I have the Gear Reduction TU in my KING TIGER and they are sweet! I have about 4 youtube videos driving with them!
You have to break them in though a lot, or they are noisy ( not broke in ) also and will put load on the electronics! I pulled the gear reduction out to check without and I now have Tamiya scale speed and they are much quieter! My second set will get broke in properly!
The Blitz