Under the valve cover - 2002 Outback H6

Why would you use G-Powers? :unsure:

They are inferior to the OE iridiums and won't last as long. 60k is probably the upper limit for G-Power, while iridium should be able to exceed 100k. Better yet, ruthenium might have been worth it, too, especially considering how difficult the job is on that car :D

The blue gaskets look cool :cool:
Because the g powers will last for 60k miles.

And at that point, the plugs are out lasting the rest of the car.

The engine may well have another 100k in it, but the rest of the car does not.
Trop Arctic Oil is not a quality oil, which is probably how it started with the sludge and varnish, and 10K oci's with a good synthetic didn't help. Combined and there lies the reason for the varnish and sludge imo. 10K OCIs are not for everyone.
Read this note again and again until it sinks in. This is one of the best Subaru engines going, and even at this point should not be anywhere near that varnished/dirty. Amazon, Quaker State Full Syn, a decent filter and 5k changes are your route to righfully claiming your next hundred thousand miles. I agree that Trop Arctic is not an oil you'll find in Victory Lane, but the issue here is OCI.