Welcome Philzorz
,
Yeah the Subaru EJ Motors definitely have a fair bit of blowby, especially if you run higher boost than stock (with eg a mods and/or a tune) - so a catch can is always a good idea.
That catch can seems like all cheap chinese Ebay stuff - stay away "The bitterness of poor quality remains long after the sweetness of low price is forgotten". Even though the seller is Aus based. It doesn't even say what the filter material is, just lists random cars that it's supposed to fit....
And it's not really legal to have a vented one (oil vapours get into the atmosphere). I know we don't have emissions testing, but the cops could fine you for that if they feel like it.
And even if you're not worried about that, the size of that one is an issue. The GT engine bay is pretty tight, and that catch can is pretty big. And because it's recommended for EJ engines to have a catch can for both the Crankcase ventilation and the PCV - without joining them (because they're under pressure/suction at different times), fitting 2 of those will be a struggle.
I'd recommend one of these Catch Cans, specially made for our cars. I'll send you a PM with the details. It has 2 separate chambers (2 IN Ports, 2 OUT Ports) in a slim design:
http://kapindustries.com.au/ Doesn't list the catch cans, but that's the company.