Yes, you definitely need butt floss to get the most out of these. Try eBay.
Once you acquire said butt floss, you will be able to enjoy PowerMax, Cathe's most supreme, best, top of the line, fantastic, superb, all-out fun work out ever. It's my absolute favorite. I love her weight work, but PowerMax is what made me a fan, back in 1996.
I think I have StepFit, but have not done it in a LONG time.
And, I don't know anything about Step Works.
So, it's worth having just for PowerMax, in my opinion.
anne