My Showroom (the main menu garage) on XBox Series S looks fantastically bright, vivid color, and clear.
I also noticed a few things seem better when viewing my car in the showroom. My Series S ray tracing performance seems vastly cleaner. Much faster rendering, with far less noise.
Metallic effects on paint and wheels looks better to me, and metal flakes in paint seem more distinct and clear now.
Best of all, before Update 8, nearly every car interior was almost completely black inside. Now, I can see detail all in the interior that before had been just dark, black, noise.
Related to the under-hood rendering being better on these cars, I also used to constantly see a dark gray-black texture used under hoods and around engines, and it had horrible blocky squares in it, as though it was either low resolution or unfiltered (probably both).
Now, I am not seeing this. Areas where I suspect it was, now appear to be filtered and have a smoothing.