Hey @Joska_unofficial
Barra into sierra sounds pretty tough.
Lots of good info on this site, have a bit of a read through these sections;
https://www.fordxr6turbo.com/forum/forum/231-conversions-transplants-and-frankensteins/
https://www.fordxr6turbo.com/forum/forum/123-300-club/
https://www.fordxr6turbo.com/forum/forum/152-400-club/
And this thread
Late 2008 onwards (FG & FG-X models) turbo motors will handle your power goal with ease with some valve springs, oil pump gears are good insurance.
Otherwise you can go the N/A + built option of course.
Injector Dynamics have a reputation for being the best for this application, Bosch 1000s will do the job though.
Turbos - the factory GT3540 with modified turbine housing (enlarged port & flap on internal wastegate) has worked well for a lot of people, mine with billet compressor wheel makes a bit over 400rwkw on 98 and just under 440rwkw on e85.
Since your best option is probably buying parts in from the US, I'd be going the gtx3576 gen 2.
If you could make the standard intake & exhaust manifolds work you've be laughing, but as you've said not likely. An aftermarket plenum like Plazmaman's retro conversion is something to consider; definitely not cheap but they've been especially designed to suit engine swaps for old Falcons, Capris, Cortinas etc so could save you a lot of pain. Hit them up with an email.
https://plazmaman.com/product/billet-ba-bf-fg-retro-conversion-manifold/
RE actual motors, there are a couple of guys on here from the US - Florida I think - one of them has imported 5 or so N/A barras for these sort of conversions.
May be worth a look considering your location?
@Mustangman570 & @SelectivePC
All the best man, look forward to this build
PS. Your English is expert level compared to some of the tards that jump on here from time to time...