I just added a 92mm Noctua exhaust fan to my T3600 with good results. The first test showed the max CPU temp drop 10 degrees from 70 to 60 while playing GTA V. The GPU dropped 7 degrees. The cores are currently between 28 and 32 degrees with Chrome open and music going. The ambient temperature in the room is 70° F.
The Noctua NF-A9 PWM is $17 on Amazon and comes with a Y-adapter that worked since I already have a 4-pin Noctua fan for the CPU. That heatsink upgrade dropped the CPU from 80 to 70. You'll need another adapter to go from the proprietary 5-pin socket on the board to the 4-pin fan connector. Both fans are running full speed since the PWM wire doesn't seem to work on either adapter I bought, but the Noctua fans are pretty quiet. I noticed very little increase in noise after adding the case fan.
I'd recommend doing this without the heatsink in, but I was able to install the case fan with the heatsink in place. I unplugged the USB header and pulled the GPU to get that lowest mount pulled through.
Tip: Put a tiny amount of liquid hand soap on the silicone mounts and they'll pull right into the fan using a pair of needle-nosed pliers.
Don't do a dumb like me. The fan will be in the way of the stupid locking bracket thing for the case's side panel. It went on without any trouble, and it wasn't until I tried to remove the panel that I realized it was STUCK. The mechanism has to go down when the lever is pulled, and the fan was in the way, preventing it from releasing.
Once I finally managed to pry the panel off, I took a rotary tool to the stupid thing and very poorly cut about half of it off so it will clear the fan.