Seriously, dragging that around (or even solo) you are unlikely to see any difference at all.
The only thing you might get is less brake fade with upgraded discs and pads, but I have never had a problem, even when up at the 3500kg max, in fact, the more I tow, the less I use the brakes. Lots of anticipation and using the the throttle and gearbox on approach to junctions means you can often not touch the middle pedal.If you are braking hard and long enough to get bad fade, perhaps merely adjusting driving style will be enough, and much cheaper too.