In my humble opinion: It depends on who you are and what state of fitness you are in. If you still have that crazy wrestling conditioning, then no, the workouts will be a breeze. The Chest and Back as well as The Ab Ripper might be the only exceptions, though after the first week it gets progressively easier. Mind you, I did this before I started training with a Wrestling conditioning coach at another High School. I'd say as a Wrestler, I was barely in good shape and still managed to breeze through most of the workouts over Summer.
BEWARE: The Plyometrics routine is overrated, even if you try and go at least 90% the whole way through.
Granted, I still do the Ab Ripper X (or whatever they were called). That's a great core workout.
I know a lot of athletes and former Wrestlers and Coaches use it with great results, but my suggestion is to stay away from P90X if you're already a decent level athlete, or a regular Wrestler.