Great write up! Been using their hoses for years - with rare exception - I wouldn't use anything else.
Hose D and G - those I had issue with. Those are for the transport of oil vapors (PCV) and oil isn't friendly (in my experience) with those hoses. Hose D in specific sheered off - it look like someone cut it STRAIGHT at the top end of the breather of the head itself - the heat, bend + less than friendly oil vapors.
Absolutely everywhere else, no issues.
I've also run their hoses in other vehicles like both of my wife's (1 wife, 2 cars) Outbacks and my 1986 Mr2 - stellar results in all 3 vehicles!
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I've heard of a magical coolant hose that runs UNDER the throttle body (2006 WRX in my case). Just curious if I missed something, as I cannot find it on your WRX.
Thanks!