Valve problems are typically few and far between on red engine cars and can present themselves in a few different ways. I would think that the two most common would be a misfire or burning oil. I cannot think of the last time that I diagnosed a car as needing a valve job because it has "valve problems". I always end up doing a valve job because the head is off while doing a head gasket. The official Volvo doctrine on you turbo motor is that the exhaust valves are Stellite coated and cannot be machined because of that and must be replaced. I have always adhered to this until recently. My machine shop says that they know of this but that they have been machining these types of valves in many types of cars for years with no problems. A full hit valve job on a B230FT can get spendy so I have opted of late not to replace those valves in lieu of machining them. What kind of problems are you experiencing that lead you to believe that you have a valve problem?

Mark