P90X with something else?

I know a lot of you are either doing P90X or have have done it in past. I am in my 4th week (first recovery week), and so far its been going good. I have only skipped a couple of yoga sessions (mostly because I feel they are too long, but I have done yoga a few times and I like it). I usually work out in the evenings after work, and I can power though the work out and usually keep up (loosely speaking, because I am not doing 40 pull/push ups like they are) with the instructors. Like Tony says, I do my best, and forget the rest.

Although I have to admit I do have a hard time sticking to ab-ripper after a full workout.

Okay, so, coming to the point. I am wondering if any of you have thought about augmenting your P90x with another program (say insanity, or 10 minute trainer, or just gym machines for that). I know that's a lot of work, but if I try to do the additional exercises in the AM before work, I should still be able to work on in the evenings. Or the other option would be to do some warm up such as running a couple miles and ap-ripper at a separate time (AM?) to make evening workouts easier. I'd likely only do it on weight training days, because cardio days are tough as it is.

I know there's a slight danger of over training, and I recognize I'd have to up my food intake to feed the body. But how much is too much?

I know it varies from person to person, but have you felt the need to make it even more extreme (i.e. additional work outs)?

PS: I recognize that there are tonnes of videos on youtube of people who've done both P90X and insanity hybrid. It seems like they all got major results, but IDK if they were on steroids or were taking stuff to be not quite as sore, or lifting 100lbs where I am doing 25lbs. Also, I am not sure how much rest (sleep time) they could afford. I am limited to 6-7.5 hours due to various reasons.

PSS: If you are considering doing, currently doing, or have done P90X in past, friend me. Thanks.