01 VDC, 05 R Sedan, 06 BAJA EJ257
Yep, no time like the present to get all the maintenance caught up. You will know where you're at. May as well do the trans fluid and filter, diffs, alignment, lube everything, balance the tires, flush all the fluids.Oil on spark plugs means you have leaking spark plug tube seals which could be causing the spark plugs to foul and misfire.
I would replace the spark plugs, tube seals and valve cover seals and sparkplug wires.
You are also due for the timing belt service (every 105,000 miles). Timing belt, all idlers, tensioner, cam & crank seals, possibly water pump.
It also may be a good time to do the headgaskets if they are leaking, most of the time on this generation of Outbacks it is an external oil or coolant leak.