Yes the Mod is quiet notice the silent part of its name.
I have the 600w version in a build and i can't hear it over case fans.
It's modular which will make your build and cable management easier.
It has a 135mm fan as opposed to the stealths 120mm fan.
Generally the larger the fan the quieter.
It's a more expensive unit offered at the same price.
It's entirely your choice i know what i would buy.
Go to OZC's website the Stealth series is entry mainstream level.
The MOD series is high performance/gaming level and very efficient power wise.
PCI Express® based PC is required with one X16 lane graphics slot available on the motherboard 500 Watt or greater power supply with two 75W 6-pin PCI Express® power connectors recommended (600 Watt and four 6-pin connectors for ATI CrossFireX™ technology in dual mode)
Certified power supplies are recommended. Refer to http://ati.amd.com/certifiedPSU for a list of Certified products
Minimum 1GB of system memory
Installation software requires CD-ROM drive
DVD playback requires DVD drive
Blu-ray™ playback requires Blu-ray drive
For an ATI CrossFireX™ system, a second ATI Radeon™ HD 5870 graphics card, an ATI CrossFireX Ready motherboard and one ATI CrossFireX Bridge Interconnect cable per graphics card (included) are required
You will need a cpu cooler if you plan to overclock to 3.6GHz or more.
The Antec 902 is a nice case and cool and quiet with fans on low.
I should know i have one.
Your best value and performance cpu cooler is the Scythe Mugen 2 rev.b if you can find one it's a consistant top 5 cooler on any test i've read.
If you can't find one i recommend these over Akaska