Pulled the hubs apart for a look and lost a bit of the silicon fluid so scraped about a level teaspoon out of the GU hub [all i could get out of it] and added it to the GQ hub making it roughly the same as before or maybe a touch more.
didn't have to remove anything to swap the fan assemblies over.
Remains to be seen if it makes a difference to the running hot under load.
GQ fan sits further forward by about 3mm ... centre section of fan blade is about 6mm less diameter making the fan blades 3mm longer, there is 8 blades instead of 7 but overall blade area might be about the same, blade pitch looks the same, outer diameter of fan blades is the same, i'm thinking the GU blade will flatten out slightly at high revs as it is more flexible
