If you're new to the whole aspect of droop do as the shop guy said and don't use them- atleast untill you've had time to do more research on the subject. Those that don't understand what or how they work are best advised to not use them as they can create a lot of havoc with your tweak and weight shifting when not set correctly.
If you check out the TC3 thread there are a lot of folks that can steer you straight on that subject since different cars seem to react to different philosophies.
Best