because the oil draining from the turbo is frothy and aerated, drain line diameter is very important. too small a diameter line aerated oil won't drain quickly enough. wrong pitch of drain line, oil won't drain correctly.
that kit from Gilbert's gbody just looks cheap. multiple pieces threaded together to make a fitting when there are billet aluminum adapters readily available as one piece units. no where are there any specs for that rubber hose.
IMO, the $ would be better spent towards EITHER the reproduction of the OE drain line available from many vendors like Classic Industries, Kirbans, OPGI, etc. links below.
OR the braided hose + fitting assembly from either Mark H. or @BobbyBuick
. links below
choice depending how the rest of your engine compartment is fitted...bone stock or modified...
OE turbo oil drain line links =>
braided AN hose + fittings assembly =>
from Mark => TURBO DRAIN KIT
from BobbyBuick => Turbo oil drain line