Turbocharged engines produced by Subaru to date require special maintenance procedures, especially if subjected to heavy acceleration or high-rev downshifts on a regular basis. Technicians MUST check the mesh screen inside the banjo bolt that secures the tubo's oil supply line to the back of the right cylinder head AT EVERY OIL CHANGE. Prone to clogging; will starve turbo leading to premature failure. ALSO, Improper oientation of the screen will restrict oil flow to the turbo. Coking in the line is common, especially if oil change intervals have been extended on a regular basis.