Good link!
So the most frequent thing there is the oil changes, which Subaru recommends every 3750 miles on all turbo motors. If you run a good synthetic and check your oil with a Used Oil Analysis, I imagine you can push well beyond 5K. If you want to play it safe, 3750 is cheap insurance.
The spark plugs - OUCH! New spark plugs every 15K miles??? WOW. I'm pretty sure the NGK plugs that most people switch to can last at least 30K, but maybe I'm wrong. 15K is just ridiculous.
The fuel filter every 30K is also questionable. A fuel filter is a fuel filter is a fuel filter. Doesn't matter how much you're trying to suck through it.
The tranny & diff oil every 30K is cheap insurance if you beat on the car a lot, but that is borderline overkill.
The coolant change and brake fluid change every 30K is actually what all cars should have, but most can get away with longer intervals as they aren't driven as hard as one would expect an STi to be.
Altho on the new STi's, they switched to a super long life coolant, which I think doesn't need to be changed but every 100K? Crazy
Really that service interval is very conservative. If you maintain that religiously, the car's drivetrain should last damn near forever.