An oversize turbo intake pipe would benefit you search for more power, they are reasonably priced and not difficult or expensive to have fitted. I believe these work best with an open cone style filter. Exhaust manifold can be replaced with better flowing aftermarket option although options are limited, best bet I think would be a ported China fold, these are available on Ali express and not crazy money either but you would need someone to port it (port specs available from Badger 5) which I believe is time consuming but you could have a go yourself.. Already mentioned 3inch downpipe is a must. Bigger injectors could benefit your set up but would require custom mapping.