as a scoobie owner IHI twin scrolls are NOT cheap and the header you’d need would not be a cheap fab for a I4… a VF22 which is an older JDM STi turbo is a non BB IHI turbo, it’s good for ~350AWHP ( on a 30% driveline loss) with a spool at ~ 35-3800rpm. THE VF39 BB is also an option but it’s more then a VF22 (~$ and designed to make 300ish on a 2.5L at ~3200).
other options, other then garrett are the Td05-20G or a Holstet HX35
nothing beats a built rotory baby!!