Hi Skinny,
No, CTX Kickbox is different from CK. CK is very cardio-routine oriented for most of the workout, but uses kickboxing moves within the cardio. It is a highly intense cardio workout, IMO. There is a drill section, but it is separate from the cardio workout. The cardio workout including warm up is about 40 minutes; the drills section after the cardio os about 15 mins.
Kickbox is more drill-oriented, all the way around. It is still intense, IMO, but definitely not as intense as CK. There IS a section that I'd describe as a jumprope-into-plyos interval, about 15 mins into the workout. So it is still intense as a workout, even though it is short.
HTH
Kathy