Yes they did. . . Not mine, but I have a buddy who has one that looks like it.
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I believe (not a fact) that the car was originally going to ship with a water or water/methanol injection system. I'll have to check with my friend, but I thought the dash panel had a spot for a light and some wiring in the loom. I don't think it ever shipped that way, but again, could be wrong.
His dad had an actual GN, not just the T-type. Ironically, I think the T-type was the faster of the two due to weight and accessories. Not sure about a GNX, maybe it was faster.
Anyway, the fun part for me about this car is that my mom had a 4 door Pontiac Bonneville of a similar year. The inside is vintage 80's GM velour bench seat etc. and it is the same in the T-type. You think you're in a grandma car until you push the pedal. It handled about the same too.
The last iteration of his car made around 600 hp, I think - still on the v6 platform. It would be way cheaper to put an LS in it, but he's committed to the v6 platform for various reasons. He wasn't the first owner, but has owned it (and done various engine packages) since around 1995/6, I believe.
Next time I see him (likely March, as he works for a NASCAR team and they are busy now), I'll get a pic of the version I've ridden in.
Sandy.