just don't lock it when your making tight turns in carparks or doing slow u-turns, it will make a horrible clunking sound as it winds up and will put all sorts off stress on your driveline, much like a 4wd withg the front diffs locks on tarmac
i lock my dccd up if its pissing down with rain as it takes away that 'taily' feeling you get with 65% rear drive (almost feels like no front drive at all)
i also lock up the dccd in the dry for spirited driving, have a bit of a play with it, mine feels mad as i dial it up through long sweeping corners whilst applying the loud pedal, can actually feel the drive going more towards the front as it 'pulls' you through the corner nicely