I wouldn't put 'shockproof' in a Subaru Syncro box, as George says, don't skimp.
The chap I buy my oil from, and take advice from, is Alyn at AS performance, it's fine being a 'shipper' of oil like Opie, selling in bulk, but AS have the experience running these boxes competatively, experience is everything, no brainer to me.
---john---