Just as with spring assisters, varying away from the manufacturers specification should be avoided. It will change the ride characteristics and that might conflict with any of the electronic stability Programmes fitted to the vehicle. Don't forget it is a modification to a standard vehicle and your insurer must be told.
Certainly in some models of car, the ESP has sensors that monitor the cars body motion and it produces correction signal accordingly. If you change the bodies motion characteristics by fitting spring assisters or damper rates, that will produce erroneous signals and the ESP will not provide the correct output signals That is most likely it will under estimate the conditions and therefore not provide enough correction.
The other misconception that abounds, is by fitting uprated springs it will allow you to tow or carry heavier loads. It does not. The cars weights specifications remain unchanged.
If you are unhappy with a towing characteristic, don't change anything until you have checked your current loading, and had your existing suspension and tyres fully checked out.