Not a problem, because I can match the MAC address in the DHCP server leases. Also, since I plan to set these up in one LAN (at home) and move them to a data center (a different LAN), what I will do is specify the fixed IP for the units in both LAN's DHCP servers. This way I can just move them from one LAN to the other and they will have predictable IP addresses without needing to change the IPs in the S3s themselves.
For stuff like this, I prefer to use DHCP to dole out static IPs because it centralizes control over the IPs in the DHCP server rather than distributing the config across a bunch of machines. Just my administrative preference...