For those into Corvettes, this might be of interest. I came across these UK magazine test times. I think they show what a showroom car can do. Since they were export cars, it's unlikely they were enhanced for magazine testing.
'82 TBI 350
1968 L68 427 4 speed 0-60 6.1 seconds top speed 145 mph (Motor)
1984 TBI Automatic 0-60 7 seconds top speed 139 mph (Motor)
1984 TBI Automatic 0-60 7.2 seconds top speed 138 mph (Fast Lane)
1984 TBI Automatic 0-60 6.6 seconds top speed 142 mph (Autocar)
1986 TPI Stick 0-60 6 seconds top speed 151 mph (Autocar)
1989 ZR-1 (380 hp) 0-60 5.6 seconds (Autocar)
1992 LT1 Automatic 0-60 5.8 seconds top speed 162 mph (Performance Car)
The LT1 car did a 14.3 second 1/4 mile at 100 mph in wintery conditions. The ZR-1 beat the 1986 car in 30-70 mph acceleration 4.5 to 6.3 seconds.