I myself am not too knowledgable on the Bullit Stang, but I do know what you mean about uninformed dealers. There is nothing like asking a couple relatively easy questions to a sales person and all they can come up with is some BS to try to get you to buy the car. You would think that with all the down time these guys have that they would educate themselves on the models, options, availablities, etc.
If I do get some cheesy sales dude that hasn't got a clue, I usally just tell them I'm just looking and then find a new sales person and ask them the same question.
Sorry to ramble - My vote would be for you to stick with your 92GT and drop in a healthy new stroker motor!
E
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1991 5.0 LX Coupe -37,800 miles
13.17 @ 106.14 mph w/ 2.138 60'
Pro-Charger D-1SC on the way!!!