Originally Posted by johnnyt
thanks.. between the two, does 3cm make a big difference?
Yes 3cm of effective edge makes a huge difference especially on a RC board. It already rides loose as it is, at 185lbs you'll want the stability of a 158. The only reason you'd want to size down to a 155 is if you're were going to do ride park, in which case you wouldn't want the SL to beging with, you'd want the Proto.