My friend tells me that lapping valves is a must when replacing them. I again have heard that lapping will destroy some special coating on valves and so valves won`t last for too long. Some say that you can do lapping to stainless steel valves. Is this one true? Also I read from somewhere that lapping is acceptable for only stainless steel exhaust valves. Is recuting seats the only right decision to make? If I would recut, would i still need lapping? My friend is sure that lapping is needed in one way or another. I am really confused on this topic. I doubt I will need a valve job any time in near future, but it would be good to know the right answers when it comes down to it.