My mom had an 80 gran prix.
3.8 was super gutless but would not die.
Trans eventually took a dump.
I've never seen a manual trans one, though.
That's one of several motors I just don't get the mystique over.
327 and 351c are others.
Never had a 327 but did own a 351c-4v so personal exp with that and the 3.8.
Neither was anything special.
Those early 3.8 liters were gutless but like you said...they never would die. Go for a ride in a Pontiac Bonneville SSEI with the supercharged 3.8 probably around 1996 vintage.