hmm you sure you're not looking at the carbon canister, i've only ever seen the 2 hoses come off the filter, its obviously pressurised so i can't imagine how you'd have a purge line coming off it

you'll need an ecu to get it tuned unless you want to pay $2k+ for an ecutek, in with case i'd suggest going for bigger turbo too

cheapest way to tune would be to get a unichip (type a for your model) i did this when i had my 99 gt foz, with a vf22 on it i got about 160kw atw, felt great, i would suggest getting something a bit less laggy though like a vf34, your stock injectors will handle this fine, there a is a boost control module that comes with the unichip & you won't need a boost controller

if you don't tune the ecu you may aswell just get a boost t, this will work fine (just block off the stock boost solenoid line) but you'll only get about 11psi before you hit boost cut, and it will boost spike on cold mornings even when set to lower boost

have a read of this, its like the holy grail of starter mods for the foz:
https://www.mrtperformance.com.au/st...T-Forester.pdf

might want to join ozfoz.com too, great info on there too