I just installed (within the past week or so) Koni FSD's on my motorhome, replacing the apparently original 18+ year old Ford shocks. They seemed to work nicely on a test drive, though it wasn't especially demanding conditions. How much of that is simply due to having shocks that are not old and in questionable condition rather than the fancy FSD valving I can't really say.
On the fronts, I ended up using a flex head ratchet wrench on the top nut and a plain wrench on the shock barrel. (The '98 E-SuperDuty chassis has no floorboard access hole on the passenger side, and the one on the driver side is not really big enough or well spaced to be much use in unbolting the shock; it's main purpose is to feed the shift cable through.) Of course, the OEM and Koni shocks use different size fasteners, so I had to buy two different flex head ratchet wrenches. The Konis required a 19mm one, which was not too easy to find locally, but 3/4" was more readily available and is the same size for any practical purpose. (3/4" is theoretically 0.05mm oversized. I don't know what the manufacturing tolerances are for wrenches, but it may well be larger than that theoretical difference.)