AHThe idea to "D everything" originated from one of you. LOL.
You probably read Thinder's 'advice' which seem obsessively focused on min-maxing, and not even in a good way. Like stripping FSDs down to a size where the ship (with a combat focus) literally cannot jump to another system, all for a few extra decimals of turn rate or meters of speed and whatnot, or using "stripped down" as an experimental for the FSD when there is no benefit to speed and negligible increase in maneuverability. I tried to provide some improvements to a build and was just repeatedly told I was "enforcing my viewpoint" despite simply pointing out how the build could be made better without it getting turned into something it was not supposed to be (and not actually losing anything, only making it better).
The only time a D rated FSD - as I have heard - is actually beneficial is with the SCO drives where on smaller ships (like the Imperial Courier) get more range out of a 3D due to its lower weight while retaining the same base jump range as a regular A rated FSD. But you lose out on overcharge performance with that.