I've had a HEQ5Pro for over 2 years and was considering the Rowen belt mod, but after checking the characteristics of my mount I decided not to go ahead at this point. Few things to consider:
1. The Skywatcher warranty is void once the mod is done, luckily I had to claim warranty on the mount recently which got replaced with no issues.
2. Sound of the mount is only a problem when slewing, when using for astrophotography I probably slew 3 times a night, If you are a visual observer then its annoying.
3. Backlash, how much is it and what is it limiting you to do ? I can do 60sec subs repeatedly without guiding on my setup, with PHD2 its 5mins or greater.
Rowen belt mod makes slewing quieter, accurate but how much more than what it is now ? What is the current limitation, that it will make better ?
Personally my opinion, unless your setup is close to the limits of the mounts payload capacity go for a Rowen belt mod, other than noise reduction it is a warranty voiding exercise.
This was my thought process when I was considering one more recently.
