I need a step on the side of my K5 - both the wife and the carpool partner struggle to get in, and they need some assistance. I am looking into the Carr steps. They have a "Super Hoop" that is 20" wide, and a "Hoop II" that is 10" wide. The wider one gives more assistance to somebody getting into the back seat, but I like the narrow one because it is less obtrusive. Has anybody had experience with the Carr step on their K5? Which one has worked better - the 20" or the 10" unit? And ... should I go shiny, dull, or black?