19: 1989 Pontiac Turbo Trans Am
The Buick Grand National was a surprise hit for GM, even though it only had a turbo-charged V6 engine. That meant the company could experiment with other performance models at the time. The Firebird Trans Am was the next logical successor, due to the platforms overwhelming success and aging V8 engine (via Barrett Jackson).

The 1989 Pontiac Turbo Trans Am was produced in low numbers. The car utilized the same engine and drivetrain as the Buick Grand National. Whether you liked Pontiac or not, the car was influential for having a V6 engine. This variation of the Firebird was released long before turbocharged V6 engines had become the norm as they are today.