the one comment that i would add to all of these is that i think with crossfit your diet is very important esp when trying to stay lean. seems most are sold on the zone or paleo. right now your running is probably contributing to your leaness. you may have to keep this up some unless your diet is right on. but xfit will give you a whole new perspective on fitness. the only thing i would add is that xfit is a program to enhance your general physical preparedness. if your goal is overall excellent fitness then this will do that for you. if you have other interests such as triathlon, powerlifting, climbing, biking then you will still need to do these but xfit will enhance these activities.