At this month’s 2023 Goodwood Festival of Speed, former Formula 1 driver Stefan Johansson will unveil a modified Porsche 911 he hand painted. It won’t just be any 911, though. Instead, it will be powered by one of his former F1 racing engines. The car—code-named SJ87—is the eighth of 11 Porsche 930 TAG Turbo builds by Lanzante, a…