Which would be better?

i have a thermochill 120.3 and can't decide b/w these fans.
I want it to be quiet.

all panaflo fans 120x38mm

1)ultra low speed=68.9 CFM @ 1700 RPM, 30 dBA
2)medium speed=86.5 CFM @ 2100 RPM, 35.5 dBA
3)high speed=103.8 CFM @ 2500 RPM, 41.5 dBA
4)ultra high speed=114.7 CFM @ 2750 RPM, 45.5 dBA

now i know if i want quiet then i should go for the ultra low, but if i decide to go with the other ones i'll get a sunbean fan contoller and always run it at a lower speed. My main question is that if get the higher speed fans and just lower would it be better( more air, pressure, low noise) than the ultra low or medium. I have heard the medium and ultra low fans, but not the other two. The medium has a slight hum at full speed and as soon as you lower it to about 80-85% its quiet. Also how do the high and ultra high react to lower voltages? do they vibrate or are they smooth and silent?

thanks and anyone that has any of these fans please post some feedback
thanks

What are the model#s? A sleeve fan is quieter than a ball bearing fan of equal RPM.

Certain fans do not take voltage lower than rated very well(can cause an annoying 'clicking' sound). Some don't run below 7v at all.

It all depends on exactly what fans you are looking at. Specs really mean nothing.

they are all panalfo hydor bearing fans

Which 120.3 the HE or the PA? For the PA the L1A's would be more than enough... for the HE id go with the Mid M1A's on a fan controller. Heh, I'd put the L1A's on a controller as well.

he series

i have 2 of those ultra high speeds u1a i think and have them both on a fan controller, theyre pretty silent not sure if they vibrate tho but both of them on max is still pretty loud not anywhere close to one vantec tornado on max

at the silent speed, do they push a lot of air, or does it seem pretty weak?

completely diferent fans will work as well if you only want low noise you can go with 120x25 fans
you didnt give a real clear goal . you said quiet but if that was all there was to it you whould not be asking about 30 db fans

are you overclocking and if so what parts?

if you arnt OCing then you want to go with the quietest fans possible because the extra cooling from the larger ones will mean absolutely nothing to you since your system is not making use of the extra heat disipation

you mentined, picking up a fan speed controller as well, so if thats the case, might as well go for the medium and high speed and using the fan controller. This way you more options available to you for airflow and noise.

i think i will go with the high or medium,
and yes of course i will be overclocking. i have 2 evercool 25mm fans right now and they are quiet at 30% of full speed, but now that much air is being pushed out of them, so i wanna give 38mm's a try and i personally like panaflo fans