I know this is an old thread, but just poking my head in here after finding it via search. I wonder how the OP's doing?
I started Insanity with a friend like a year ago, we didn't get very far (we were enjoying it, but work schedules mucked it up, blah blah excuses).
I started it again two weeks ago on my own, and am having a great time. Shaun kicks my ass really hard, as everyone else has said. My biggest concern right now comes from some googling (as concerns often do). There are some people posting reviews/blogs about how terribly injury-causing Insanity can be. Lots of discussion on back, knee, wrist injuries resulting from the workout. I'll be honest: I'm not overly worried about knee or back problems, but I'm a professional pianist so shoulder/wrist injuries would be a BIG problem for me. So far, I haven't had any pain other than normal workout-soreness, but I'm only on week 3 and some people write about problems not setting on until weeks after they finish.
I use pushup bars to keep my wrists in line, take more breaks than the people on the video and try to go at my own pace (while still pushing myself pretty hard). I confess I skip a couple exercises that just seem like a bad idea for a pianist (tricep dips, V pushups). Do the gurus here think I'll be fine so long as I pace myself and listen to my body with this workout routine? I want to keep getting in shape, but I'm paranoid about screwing up my career over it...