Muy Thai also untilizes the clinch a lot as well where kickboxing does not. I personally think that Muy Thai is more devestating than kickboxing because of the knees from the clinch.
Just make sure that you maintain your cardio and stretch like others have said.
The 2014 Hit Squad (FFL)
Eddie Alvarez - Junior Dos Santos - Patricio Freire - Jessica Eye - Pat Curran