Originally Posted by downest
As far as I know Subaru coolant is green, requires mixing with water, and also requires a small bottle of cooling system conditioner. It has a service life of 30k miles, which is why it's listed as part of many 30k/60k/90k services.
We use Honda coolant, which is blue, already mixed, and lasts until your engine has to come out for pistons/spun bearing etc (Honda rates it at 10 years/120k, not too many turbo Subarus go that long without major engine work). It's available at your local Honda dealer for just under $20 per gallon.
The green coolant is regular Long Life. They stopped using that in 08 / 09. All 08 sti's have the new blue stuff and all 09 up Subarus have the blue stuff. The service interval is pretty much the same as the Honda, pretty much lasts forever. Although I like changing it anyway.