"Is that fan loud? the sunon 108cfm one. Are you using just 1 fan?
I might go with that sunon but use 2 instead. But the ys tech has more rpms, which should lead to be better pressure."
The Sunon 108cfm fan that I am using is rated @ 42dbls however I sanded the blades with 600grit then 1500grit and I beleive that it sounds more like 39-40dbls now. It is not THAT loud but it is noticeable when I walk into the room. It is NOT like those delta screamers that you can hear 2 rooms down the hall.
For me, I can barely hear my (4) 7200rpm SCSI drives over the fan so in my book, it is quiet enough (except that it is starting to make a "whinning noise"; probably because it is almost 2 years old)
Yes I am using only the Sunon on my heatercore with a shroud and I can feel the air comming out the back of the heatercore from about 6' away.
TerraMex: Well, it was a rather large hole and I also cut several other LARGE sections out of my case at the same time. I probably went through 5 disks total. Also I dont think I had the motor on full power either

opps!)
One Last Thing: WEAR EYE PROTECTION!!!!!!