I am looking to replace an older Cipafilter firewall with a Sonicwall and am trying to select the proper unit for the network. I don't want to under power, but also don't want to buy overkill either. The network is a K-8 network, gigabit switches, 50mbps internet, about 100 nodes with around 255 users made up of staff and students. The TZ600 looks to be much more powerfull than TZ units of yesteryear. Any suggestions or ideas appreciated.