Well I got the replacement fan installed.
I also did some temperature testing with my new infrared/laser thermometer and tested the difference in sound with SPL meter app on my phone.
Stock fan produced between + 22-25 DB more output over the ambient sound of the room I was testing it in. So ambient noise in room was around 52-55 db, with fan on at approx 2 ft away it jumped to 74-79 DB with the louder sound produced behind the amp.
As a comparison I also tested my Crown XLI 1500. It only produced an extra 3-4 DB over ambient at less than a foot away from the front and back.
After fan swap the Behringer was identical to the Crown with + 3-4 DB over ambient max from 8ish inches away.
Stock fan with shroud removed produced between 72-84F degrees (at idle IE no load) all over and around the heat sink and PCB. The hottest area was the last place that was connected from the PCB to the heatsink closest to the front of the amp.
After fan swap with shroud removed and Heat Sinks installed temps were 81-95F which was a little concerning. So I replaced the shroud which helped a bit and averaged 77-91F.
Since the replacement fan was essentially silent from 3-4 feet away I can always get a higher DBA fan which moves more air if I have any issues overheating.
Some time this week or weekend I will hook up my 2 garage subs and do some testing under load and see what happens.
Note to self! Be VERY sure of placement of the heat sinks before letting them touch anything! Well at least I will try to next time