i got one from Carquest and it fit perfect when i cut about 4" off the end- and there was a white line right at the cutoff point. they didn't ask if it was a turbo car or not, so i assume all 3.8 G bodies use the same hose.
when i put the bigger Cutlass radiator in it, i just got a hose for an 87 Regal witha 3.8- again, they didn't ask if it was a GN or anything, and it fit perfect with no trimming at all.