"Show Car" can mean a lot of things. I agree with Stan's parameters in general but he's leaving out a lot of sub and sub-sub cultural trends. You know, the "stance" guys with the leaned-out Hondas and 'Yotas. The would-be "drifters." The Low Riders. There's a whole world of truck dudes out there, mostly doing stuff I'd find pointless, if not offensive. The HAMB guys' efforts almost always make me smile. Plus there are still Bubble and Box aficionados out there...somewhere. Kit car/replica guys are but one tiny pimple on the Car Guy Planet, and even among our kind there are differences in style and substance.
My issue with the SEMA aesthetic is not merely that it's tasteless money-gunnery (and kudos to @Stan Galat for coining a great phrase). It's that the cars' function is almost always forgotten. Those things—supposed "works of art"—are not only incapable of being driven on the road. Most of them would burst into flames if you attempted to start them.
At some point it ceases to be awe-inspiring or even amusing, and it becomes just...sad.
It's not even new though. The story is told about Ed Roth's Mysterion, the famous, twin-engined, Bill-the-Cat-eyed hot rod that launched a million kids' Kandy-Koated dreams, that it was was so poorly engineered and constructed that its frame cracked constantly just from travel on the trailer.
A modern replica uses a hollowed-out engine on one side to save weight.
Sound fun? Not to me. I rather have something like Stan, or Danny P, would build—close to the bleeding edge of functional performance.
—or something like I would build: with perhaps lesser acceleration but more reliability, and looks to match, as far as possible, what is being aped.
But that's just me, and that's just now. Tastes change. Who's to say in a year or two I won't be on to something radically different? The SEMA people, and all the other flavors of our flavor, keep spinning wheels and rolling fuzzy dice that the rest of us might find some inspiration.
And I like that.