A guy at the dealer today (not an employee) said that he had 50 hours on his son's 07 when one of the valves went south. He didn't say which one, but he said rather than spending big bucks on a entire valve job he just replaced the one assembly since the rest hadn't moved. To me it doesn't seem like a good idea. I'd say if you have the head off do the whole job. I'd maybe consider this with 10 hours but 50? Anyone tried this?