Rear TSB difficulties at dealership

I printed up the TSB for the rear and brought my truck in to get it done alone with a front set of bilstiens. First the guy said that he need proof that the bed was sagging and bottoming out under heavy load. after going back in forth for a while they finally aggreed to do it but told me thatthe ride would be extremely stiff and i would hate it. how stiff will the ride be, i would rather the ride feel more like a truck than a camry