Snowdrop wrote A general console to console connection will not get you banned. For example, retail to Dev or RGH. The connection via system link does not pass a LIVE check so therefore your safe. Although, Im not saying you cant get banned. If a game server picks up that you have modified stats, there is a chance.

Completely safe games to system link:

MW2
Cod4
Cod5

Any game released after MW2 seem a bit sketchy when modifying statsets but its your call.

Good luck!