Only 2-3 known people to me have made more than 200hp from a turbo A series
Someone from Ballarat, another in Finland & another in Yatalla albeit very
peaky hp with little drive-ability for the last example.

I would ask if the Ballarattian is prepared to do the work.

Use E-go.com.au 80 each way depo to depo from Sydney depo near you to
Mitchell Park to Ballarat 3355 and some petrol money time for him.

No carb will make a reliable 250+hp atw for an A series unless prepared
to pay more for tuning and setting them up and even then good luck but
no one has done it due to the pitfalls. Will need also e85 or meth.

For 100hp atw a carb can do, anything over 250hp atw efi is the only way and even then you need good money for the right Turbo, Manifolds, ecu, injectors, gearbox, clutch, tuning along with diff, brakes and suspension.

If a similar engine the Renault sierra 1.4 ohv non crossflow with smaller ports found in renault 5 can make a hand grenade 400+hp in the UK with 40-50psi by several enthusiasts spending what the queen spends on her false teeth and hats then coming close to that hp is not cheap or even remotely close with a 32/36 carby turbo unless running illegal liquid explosives like Hydrazine for a split second before your engine turns into a fusion mixed with fission reaction and driver, car and surroundings disappears faster than Skase can move millions into a foreign bank account.