Is it illegal to mod a xbox 360?

No it is not illegal. But, you can get banned if you don't buy a mod from nuclearmodz.com! You can buy a mod for almost anything there for cheap. And the best part is, if your mod gets patched or breaks, you can send it back for another one for free! Just if you do buy a mod, please referr NgC x SaT uDoWn. Thank You and I hope this helped