I did consider the U12P SE2 and even the 92mm version but really if i remove the 120mm fan from the D14 it doesn't seem any bigger in any way that matters (of course, it is bigger but if it actually fits, why not?) The D14 is pocket change more expensive than the U12P here and I really like the idea of also getting ram/VRM cooling from the bottom bit of the mid mount 140mm fan. Hassle isn't really an issue as long as the thing actually fits with the other bits i want. I agree that it's total overkill but for me that's in its favour. means i can turn the mid fan down (or remove it entirely) and still keep the temperatures super low.. I'm really obsessive about CPU temperatures - keep the temperatures lower whilst overclocking too?
For me there is no why, there is only why not. sounds like a daft thing to say when i type it like that but its true - if i can, then why not? I have a goal in mind with this build, and that is to fit a high end (ish) system into a tiny case, inaudibly and with the temperatures i like which, ideally, are significantly sub-50*c at full load.
Yep, i looked for the old FD1238s, or their modern equivalent - just thinking how good a 38mm thick fan would be with all the modern tech that makes todays best 25mm thick fans so good. Also, i figured that with the extra performance of such a fan, I could fit a 25mm thick model to the front at the same RPM as the rear and still get a bit of negative pressure to suck some air through the pci backplate (which i intend to fit dust filtered covers to) and the grille next to them which i can also dust filter. I intend to add dust filters throughout the case, on every intake vent. Irrelevant anyway because i haven't been able to find such a fan, hoped someone here would know of them if they exist which they don't appear to.
My friends actually do call me king overkill

but i'm happy with that, makes me feel like i'm overachieving.
EDIT: to save on double posts i'll edit this post. I see what you're saying sir and tis a good point. I always knew that a D14 would be TIGHT on the 3.5" bay turned 90* even with the D14's 120mm fan removed. Because drive bays are more important to me than going from high end to elite air cooling (my current rig is custom, overkill watercooled and has been since the days of the first socket A AXIA athlons) what i'm going to do is do the drive bay mod first and i may try to fit an old HD bracket from an old case with multiple bays then take my measurements and decide on heatsink then. The D14 only appears to be a little bit longer at each end with the 120mm removed than a U12P with the fan on the front end of the heatsink so going U12P wouldn't gain me any significant space at that side. I've seen coolers slimmer and cheaper than U12P that should work fine but if i can fit D14, then i would always regret not doing so if i didn't... i just visualise the case and can see the airflow from the 3 fans i want in my main chamber (not including GPU cooling) and in my head it looks better with D14 than anything else.. largely because of that 140mm fan in the middle
edit 2: I have managed to find 120x38 fans from Panaflo, Sanyo Denki(look like old tech from the numbers), Scythe (ultra kaze 3000rpm), the similarly 'No.' Delta fans, and silenx's ixtrema pro (18dbA, 90cfm) haven't decided on that silenx yet i may just fit another, probably cheaper 120x25 but based on all of about 10 seconds of research the ixtrema looks very promising