Hi, daughter in law's 09 Legacy with the 2.5 and a sudden bad skip at 98K miles.  Timing marks right on, very low compression in #4. I pulled the engine out and removed the heads expecting to find a blown gasket or sucked valve, but found #4 piston broken at the top edge at the ring bore like the ring was trying to break out.  I've never repaired a Subaru engine,  but did find a video on youtube (where else) that shows the pistons can be removed without touching the rods. Seems there's an a