you done everything you need to get as quick a spool as possible.

Maybe get some good time on a dyno to make to most of your mods.

Only other thing is a twinscroll conversion but probably a bit unnecessary for you.

And its not worth replacing the stock headers or uppipe when its under 200kw atw your after. Better flowing header will will only serve to reduce exhaust gas velocity which at this point would increase your turbo lag.

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RS Liberty - Because WRX's are only good for parts...