We just received our firewalls! YAY. now.. installing them.. grr.. i've installed very few PIX firewalls. we ordered a 506E and two 501 PIX firewalls. the 506E is for our main HQ and the other two are for our smaller branches. both of the smaller branches connect to the main branch through a VPN connection. installing these firewalls, will installing them one at a time matter? i mean, each of our locations are a few hours apart so i cant do them all at the same time and we really cant have any downtime. also, place it in front of our cisco 1700 routers? or after them?