I do not own any Cathe DVDs yet but will be ordering the Intensity series when it comes out on DVD. My question is this, I am a current Firm user and I have the "Fanny Lifter" which is basically two steps, a 6 inch and 8 inch. You can use them separately or stack one on top of the other to create a 14 inch step. I think this will work for Cathe's weight lifting DVDs but I am not so sure about the cardio ones where she has the large aerobic stepper. So, my question is this - will I need to buy a step like the one Cathe uses or can I substitute the Fanny Lifter. Keep in mind that this step is not long like an aerobic step. It is about 2 foot by 2 foot.