Well it has been 24 hours...The temperature is the same as before I put it in the box (actually 1 degree lower). The key to this whole design is the fan I put on the exhaust side. I just pulled a computer fan off an old computer and powered it with an ac adapter. The air moves very well. Keep in mind this is a budget model, I'm sure you can find better foam. The foam high density urethane from a craft store, on sale for $4.99 a yard. The server is not sitting on the foam directly, it is sitting on legs (little pvc pipe couplers)
As for the DB reduction. The difference is amazing. I wish I had a more technical description but... it went from a shop-vac to a microwave.
Please pardon my crude drawing!
Well I can't say i've ever heard the hard drive, really hard to hear anything over the two 13,000 rpm fans. The two server fans are 60db each.
And to those who WILL ask "Why dont you put it in the other room, buy a quieter computer, change the fans, put it in the fridge, put it in the closet, etc etc." The answer is , cause it was loud and free.