Toyota also tuned the engine, transmission and chassis to its own tastes.
That job fell to chief test driver Herwig Daenens. The Belgian driver studied at the hand of late master test driver Hiromu Naruse, the Toyota guru who taught CEO Akio Toyoda how to race and set the standard for the company's sports cars by helping craft the Lexus LFA super sports car.
Toyoda also had a voice in the tuning. He tested the car repeatedly during development, as early as three years ago in Germany, offering input on areas such as braking, Tada said.
"It was only recently that he started smiling a little, and said 'it has become better,' " Tada said.
Supra fans may get a sneak peek before the Detroit show. Toyota's Gazoo Racing division will show a GR Supra Super GT Concept at the Tokyo Auto Salon, which runs Jan. 11-13. A teaser shot of that car shows a blacked-out Supra with a large racing wing on the back lid.
The Supra is the first original product developed by Gazoo Racing Co., which was cleaved off last year as an internal subcompany in a reorganization to streamline operations.
Despite Toyota's sporty ambitions, the brand's two sporty offerings still rely on engines that aren't even made by Toyota. The Supra gets its from BMW. The other, the Toyota 86, gets its four-cylinder horizontally-opposed powerplant from partner Subaru, which also assembles the car.
But Toyota might not have to borrow from others for long.
Tada, who is chief engineer at Gazoo Racing, said the division is currently developing several of its own sporty engines for production cars. Tada declined to give further details, such as whether the engines are all-new powerplants or simply retuned versions of existing ones.
But he suggested electrification might play into the plans.