Just boxed up Corsair CX750M's and pulled the stock fans out of the S5's. Replaced those with Corsair SP120 fans. Replaced PSU's with an evga 1300G2 Supernova.
Right now window cracked open - running cold air intake mode! Once I figure how they will rest will secure them then get on that red cable management. What a mess.
Couldn't be happier with the new fans or the new power. Love these machines, especially now that they are liveable and silent compared to stock.

I ran the SP120 High performance on my S5's and they couldn't cut it. Ambient temps were about 65F and the temps went straight to 65 or higher. Soon as the warm weather sneaks in, those fans will not be able to cool it sufficiently. I opted for the Noctua NF-F12 3000. Used two of them on each S5 and brought the temp back down 10 degrees. A lot less noise than stock fan, but not silent either. In between, but dooable in situation.
Good luck!
Winner winner chicken dinner! The SP120's work when it is cool outside and that air is useable. When I stuck my hand to the back of the miner with the SP120 it was pretty clear there was not much air being pushed out the back. The noise reduction is so worth it.
So! Had issues with the used S5s I bought. Basically they had been to Bitmain before for issues, continued issues which were passed on to me. So... one machine should be back tomorrow, fingers crossed it is good to go.
Have my PSU's and miners right where I want them. Did not want to molex in and start adding fans. Have picked up / arriving soon a 4x Rotary AC powered fan controller. Plug 3 or 4 pin directly into it, 12v with 1amp per fan max, total of 2.8amp across the 4 fans. Have 15 fans behind me that will be picked and added. Looks like:
Scythe 1200 rpm 69 CFM fan at 24dBA to replace the stock in one S5
Rear fans - On the controller will add 2x Scythe 3k rpm and 1x San-Ace 3k rpm. Can spool those up as needed. I posted a pic of my old S1 setup with the exhaust being pushed outside. Plan to build a shroud and have these S5s dump heat right outside once the weather starts sticking in the 70s.
I love it as I get to take my stuff apart again and rewire. Want it clean! I did add a cutting board underneath to help with airflow at bottom. No major difference there.
more pics in a few days!