My story isn't about a GNX but very close from both sides of the coin. My father sold Buicks at a dealership in Denver, CO where they used the "Up" system. Basically, every salesman was in line for a customer. On a slow day, you might have some down time if you were 3rd or 4th on the list for a customer. One day this farmer walked into the dealership wearing bib overalls that had definitely been used. There were three salesman ahead of my father on the list; all three became somewhat scarce because they all "sight qualified" him. My father approached him and, long story short, the farmer left with two new cars, one for him and one for his wife. He had cash in the pocket of those well worn bib overalls.
Fast forward to 1 Nov 1992. I walk into Sam Taylor Buick-Cadillac in Ft Walton Beach FL, wearing my uniform (U.S. Air Force Staff Sergeant), looking for a car for my wife; I was interested in the 1993 Le Sabre. Apprently, because I was in uniform, I couldn't get anyone to help me. The next day we drove over to Lee Buick-GMC in Pensacola, in uniform to see if I would get the same treatment, I did not! We left with one of the best cars we've ever had, a 1993 Le Sabre Limited and made it just in time to the polling site, near home, to vote. A couple of days later, I drove it to Sam Taylor Buick and there was Sam at his usual perch at a desk above the sales floor. I asked him to come out and see my car and told him the story. I suggested he speak with his sales force or expect to lose more sales if the salesmen were going to sight qualify the customers. I still bought parts there but service was always performed at Lee Buick in Pensacola because they earned my business.