Hi Imani,
I think the videos with the fasted BPMs in Cathe's repertoire are Body Max and Step Fit. I think Step Works is kind of fast too but like Ruth said, it's invigorating! Step Jam seemed fast to me at first but I think it's just because it was made before the days of Cathe's legendary super duper unbelievably thorough warm-ups. If I use the warm up from Step Fit or Step Works instead, that makes Step Jam feel much less rushed. I think one of Cathe's best tapes with a slightly less frantic BPM is Power Max ~ of course, she keeps yelling "I want to go faster" in the video! If you're enjoying the CTX series and RS, I'd recommend starting with Power Max and/or Step Jam (with an alternate warm-up). Interval Max is really good but the funny thing is that the hardest parts of the video have nothing to do with step or BPM. All that crazy jumping just wears me out, but the interval blasts are quite adjustable so don't be afraid until you've viewed it! Hope this helps.