Hi Katia:
I have done and enjoyed the following combinations:
CTX All Step + CTX Power Circuit
CTX All Step and CTX Step & Intervals
CTX 10 10 10 + CTX Kickbox
With these I always skip the first cooldown and the second warm up and keep on going after lots of water and a bathroom stop!
You can pretty much put them together as you like!
Also, I like to do a Kickbox fest sometimes with Cardio Kicks throught to the drills, skip the drills, go straight into CTX Kickbox, then forget the cooldown and go straight back to the Cardio Kicks drills, then cool down. This workout kicks butt and you will definitely feel it in the lats and abs the next day but I love it!
Clare