P90, P90X or Rushfit?

outspan87

I'm about to start week 4 of Insanity and I'm thinking about what to do next, but I don't want to spend too much on equipment. I found a good pair of adjustable dumbbels (20 lbs each) and the Iron Gym pullup bar. I love the cardio workout but after Insanity I'll want to change it up and build some muscle mass too, and the choice will be between P90, P90X and Rushfit.

Is a pair of 20 lbs adjustable dumbbells heavy enough for P90 and P90X? (I know it is for Rushfit)

Do you know if the Iron Gym pullup bar works for sliding doors too? Is there any info on the maximum thickness of the door (I might be over)?

I wasn't very fit before starting Insanity and never did much strength training. Do you suggest P90 or P90X? If you've done Rushfit, I'd also like to hear about your experience.

Thanks!