Kart racing is a stepping stone to higher forms of motor sport like Formula 1 .. He may well be very serious about his motor sports, he'd also driven performance vehicles regularly for SS so the Porsche shouldn't have been a great novelty experience for him.
I agree it wouldn't be such a novelty. I was thinking whoever was driving it wasn't hot-dogging, but rather trying to put as much distance between himself and the crime scene as quickly as possible - more panic than pleasure. But I'm not a psychopath, so I can't really imagine what the perp(s) was/were thinking.
P.S. It may not have been a novelty to drive these cars, but he was certainly impressed by them enough to take photos and paste them all over social media. It's equivalent to these kids who post photos of themselves with fistfuls of cash - some of it from selling Jordans and some of it from dealing drugs - how can they not know that they are impressing some of their friends and painting targets on their own backs at the same time?! Possible W1 painted a target on SS' back.