Welcome to perth-wrx. As far as modifications go I would suggest the following mods. Get yourself a a good quality aftermarket panel air filter which should cost you around $100, HKS, Apexi, or even K&N. Brakes and handling mods are good area to start first I reckon. Upgraded brake pads, larger sway bars (Cusco, Whiteline). Once you post pictures up here you will also see members suggest you should drop it lower. Lowering springs or coilovers if you have the $$.

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Funny looking German Subaru