I received a Delta AFB1212SHE today and put it straight to my noisiest S5...
stock fan replacement only - no push/pull

It does need a minor modification but otherwise works rather well.
2 ridges on the connector need to be trimmed down and it will fit straight to the pins.

At this time the S5 runs a bit warmer by about 4 degrees C at 3260 rpm, but with roughly 20db less noise.

I'll proceed to replace all S5's with these fans...

Anybody know if the S4 fans are the same as the S5's?
(of course needing an extender for the rear ones in the S4)