Subaru Repair: 1999 Forester Oil Consumption, valve cover gasket, valve seals

Question
Hello, I own a 1999 Forester with 92,000 miles.  I bought it at about 80,000 miles shortly thereafter noticed that it uses a lot of oil...about a quart every 4-500 miles.  I'm seeing no leaks on the ground and the engine is dry, save a tiny bit seepage from the driver's side head gasket that I'm told is very common and not a huge concern.  It only smokes at startup though somewhat heavily, and until recently ran just fine.  In the last two weeks, it started running rough at low rpm's though and the CEL came on, flashing.  I figured from burning so much oil that the plugs were fouled, and changed them.  They were very fouled (whitish residue), and at that time I noticed that there was oil in the plug holes and on the wires.  I had it in to the dealer and they did a compression test - which came back ok...so the rings are ok.  That leaves valve seals or the valve cover gasket as the source of the burning oil, right? The dealership wants to change plugs, wires, coil, and valve cover gaskets before being able to diagnose further, but they want $900 to do this, so I'm going to just make those repairs myself.  I'm mechanically inclined and not hesitant to do the work, but I'm curious if there are any other sources of the burnt oil that I should consider before diving in with valve seals later on.  If it got too expensive or labor intensive, I'd just put in a new motor now with less miles on it and I'm trying to make that decision before spending too much on the current engine. Sorry for the length, but I wanted to get all the details.  Thanks for your help!

Answer
I would go with their suggestion but I'm not sure why they want to replace the coil. Whitish fouling is usually caused by a hot combustion chamber temperature. This could be caused by restricted exhaust, incorrect heat range or malfunctioning EGR if your vehicle has it which is unlikely now that I think of it. I would definitely replace the valve cover gaskets, wires and spark plugs and hen go from there.