rox0rs must only have one 0 replaced.
Boxz0rs can have either or both replaced, and the z is optional.
Your, can be
jer, j0r, j0 or any suitable substitute actually.
rox0rs yer b0xz0rs is one of those special cases like haxx0r and 1337 that have set out spellings regardless of your interpretation of leet.
Edit: You use a program? Thats why your leet stinks ;)