Kinugawa oil/water lines

You don't want any restrictor of any sort in the return line and it needs to run down as near to vertical as possible to prevent any buildup of oil in the turbocharger housing.
A restrictor is often incorporated in the housing or immediately before the oil enters the housing to prevent an oversupply of oil depending on type of bearings used in the turbocharger.

Advice - don’t run a restrictor.
New modern built race engine are running higher pressure (oil pump mod and relief valve mod in the case of a 3sgte), in that application they need a restrictor on the oil feed to the turbo (not drain). Do not create the restriction pressure in the turbo by restricting the drain.
Having had kinigawa stuff before, and things not fitting properly being a mr2 (not a ct turbo in a Hilux or gt4), they were good to deal with and get a resolution. Check the listing is for mr2 specifically, email them questioning if it fits mr2, then if it doesn’t you have something to go back with.