Quoted from Ferret:Thank you for buying Hot Wheels! We hope you love the game.
We're not currently thinking of having player-selectable cars, although it's a possibility for future updates. We are improving the way that we present what cars each player has collected, to show off all the really fun cars that Hot Wheels has in their lineup. Mattel has shared lots of amazing cars with us. I personally have several physical Hot Wheels cars because they're neat, even though I'm not a hardcore Hot Wheels collector... but I love seeing the various cars that pop up during the game, they're just plain fun. (Yeah, I'm on the code team, but there's ~450 featured cars, I still get surprised!) I certainly expect that both Hot Wheels collectors and casual Hot Wheels fans will really love seeing all the different featured cars.
Also: we've tweaked the spinner sound for the upcoming code release.
Since I'm dancing around it: yes, there is an upcoming code release for Hot Wheels owners. Not a promise, but we hope to release it before the US 4th of July holiday. Lots of great improvements across the board!
How many of the original 16 are in the 450? I realize there is likely a lot of licensing from the big 3 and VW that limits your use of them. Making those the "wizard" mode collections would be amazing (there are a few specific colors that are exceedingly rare as well).
Side note, I remember playing with my uncles hot wheels that were in my grandparents closet, some of which were the originals. If I could time machine back I'd tell myself not to crash those into the wall...