Hi all. Currently running a comfort spring setup from zordo in the back of my '12 d40. At the time I had a hard lid and did not carry much load. Now I have a canopy twin drawer system fridge n drop slide and feel I need to go to heavy duty leafs. My question is should I fork out the dosh and get heavy rated leafs or should I just add leafs? What have others done? Would 300kg constant load be enough? I've seen helper spring kits but have been told to stay away. Cheers in advanced for the help guys. Great site!