XLR8R

Hello all. I have a used 2002 OBW with 125,000 purchased 2 months ago from Subaru dealer. Noticed a slight ticking, had shop look it over, wrench said all is well must be piston slap. Over the last month colder weather has set in. now in the mornings very loud knocking and gets better at warm up. but not gone completely. Today I took her down to the pan to try and check for wrist pin and bearing slack. can't find any slack but did notice the bores were scored up somewhat. I really don't want to tear her down for a rebuild already. Dealer changed the oil at purchase. I have seen on this post that thinner oil may help... any ideas? Is she headed for failure? Thanks, XLR8R