Normally ships with a standard power lead so if you are going to attach it to a ups etc. you will need to provide the correct cable (take a standard kettle lead connection)
It should also come with some network cables (2 i think) pretty yellow ones. and a console cable.
The 515 is un restrict for out going licenses, incoming, max concurrent connections Concurrent connections: 130,000
http://www.cisco.com/en/US/products/hw/vpndevc/ps2030/products_data_sheet09186a0080091b15.html
If thats not enought you can always upgrade later to the UR ~256000 concurrent connections
