Hi Barbie.

Well the Cycle 1 part of BRX calls for heavy lifting, 3 sets of about 6 reps w/a 3min. rest in between. So for that I use Slow&Heavy, follow the exercises, but when Cathe's doing 8 reps or so, I'm resting. Or if its not enough time, I pause it. For C2 and 3, I've used MIS and PS successfully, usually by having the video running while I'm working out and again I follow the exercises while doing my sets and reps, not exactly what Cathe's doing but I love having it on and checking for form while I'm working out. I've been known to do MIS legs twice in a row, etc, to make it work.
Like the book says, the nutrition is 70% of the plan, so I don't think tweaking the workout is a problem at all! I don't really do much cardio..now and then I throw in a Taebo workout, its really the only kind of cardio I can stand! I've always hated cardio so this plan is tailor made for me! LOL
I'm going back to C1 this weekend and I'm going to try tweaking it a bit more, adding more good fats, coconut oil, flaxseed oil, and going even heavier on my workouts. I want that muscle!!!! Its what's eating up this #^$%#^ fat!