You should never be required to use your ISP provided all-in-one/router/modem box thing. You can always switch to a decent modem (Motorola makes decent/cheap ones for residential network at the speeds you will likely need), and put your own route behind it. As far as what your ISP can control/see they are limited to the interface device between your network and their network. If you intentionally make it a brain-dead modem then they cant see your router at all and your free to do what ever you want with no oversight.