My Scion Xb failed its warranty enhancement oil consumption test and Toyota will be replacing the piston, piston rings and related components at no cost. The dealer doing the work is offering/recommending additional services be done at a "reduced" price. They want $880 to replace the valve seals, spark plugs, water pump, PCV valve. I have previously replaced all but the valves seals and they are offering to do the work for $690. I am wondering if it is worth the cost for them do it or if it is a waste of money. Never had an issue with valve seals, so I am not sure what the chances are that it fails.