You can buy more SATA drives and gain speed through raid for cheaper than a few SAS drives. That and you get like 10x more space doing it. That's how I look at it.
I run 5-7 VMs at any given time on my main server. It has 6 1TB WD Black drives in md raid 5. Disk IO is not the bottleneck, the CPU is. (core2quad).
Hey, you're in Franklin, not Hopkinton!!
See if you can get a tour on the building on the other side of street
boxster is a chick car, get a 911 turbo on there stat.