It is surprising the number of Z owners (of all ages and demographics) even on this site that haven't driven a proper sorted TT and don't know what it is capable of, or moved on to something "faster" when their car wasn't sorted well in the first place, in their entire ownership history.
I'm not going to say its the best sports car in history. I think the 240z was a more important car overall. There are better cars you can buy today, but most of us can't afford them.
Even the Z33/Z34 does some things surprisingly well. I still don't want one though. By all accounts the GT-R is a modern miracle. But its still ugly.
While the domestic sports cars have certainly gotten faster, they've become much bigger and heavier which is why they need the bigger HP numpers. And with the changing crash test rules, the sight lines have gotten worse, making the cars feel cramped comparatively.
I think the reasons many of us like the 90s cars the best is it was the era when computers began to help, but they didn't nanny anything. And the crash testing (pedestrian laws) weren't nearly as restrictive, which is good and bad.
Finally, and I feel this is important, everything these days is done by committee and it shows. All the major brands are run by a panel of judges and it shows. I can't remember the last time I was excited by an offering from a major brand because they're all forgettable. Can you describe anything from Lexus? Infiniti? Can you name any of them? Do they make Lambo posters that you'd put on your wall like the Countach? I'd argue no.
The (quick google search) Q50 3.0T LUXE won't hold up and was built on a budget and to meet emissions requirements. Even if it trickles down to enthusiast hands, it won't put out the power that our cars can make with modest bolt ons.
Our era was fairly unique and I doubt we'll see anything like it again. Its unlikely that a contemporary car company will take a risk with a single designer like Nissan did with Yama-san on the Z32. If you haven't been to a convention, I'd get to one and watch his presentation while you can. Even if you've seen it a couple times, its fascinating and amazing that this car ever happened at all.
Finally, my car of choice for best sports car in history, is a Porsche 911. Its got the looks, the heritage, and it has changed with the times, while not forgetting what it is. I think that an electric version (since that's where the industry is headed) can still be the bee's knees. Unfortunately, price will keep it out of many people's hands. However, also a contender, the Miata.