I was generalizing.
But, since my flavour of turdbo LS is 5.3L or less it makes good sense. The 5.3L I built over the Winter has half-assed ported small-valve heads and an LS6 cam and ported LS6 intake so that will help the situation. The 4.8L I have on the floor is getting a healthy cam, some stock 241s, and a TBSS intake.
In either form they suit the GT45 turbo well.
So, if you are doing a 4.1L+ Buick V6, these GT45s would keep up alright. Employ some spooling tricks and it'll do alright by you.
EDIT: New muffler showed up today.