I wanted to share a useful upgrade I've been trying for the Tormek T-4: an improved water trough for the T-4 from Swan Prints:
https://swanprints.us/shop/product/TT4WT
One issue I've had with the factory water trough is that when sharpening longer blades, water can follow the blade by adhesion and end up outside the trough rather than being caught cleanly. This replacement trough has been valuable for that specific problem.
I also really like the built-in magnets. They are a nice practical addition and make the trough feel more thoughtfully designed in day-to-day use.
I'm still using it and forming longer-term impressions, but so far it has been a worthwhile improvement over the factory trough for my T-4.