So I've checked out some other cars and decided to re-post a list of things I think everyone wants in-game.
S-Class
Koenigsegg Agera RS - better than Regera top speed, faster acceleration than the Chiron, and handles like the Chiron. Nitro duration is not too long, but gives a little 'oomph.'
A-Class
Apollo IE - Top speed should be (with full upgrades) something like 230 mph, and acceleration should be great, since it is naturally aspirated and doesn't have turbo lag. Handling should be equivalent to that of the Camaro ZL1, and nitro should burn a little faster as to balance the stats out.
Lamborghini Huracan Performante - decent top speed, decent acceleration, good handling, and average nitro. A car designed for twisty tracks.
B-Class
Aston Martin DBS Superleggera - I've seen this car requested a lot, and I saw a review of it in Motor Trend magazine when they were doing their BDC competition. twin-turbo V12, 715 bhp, and amazing looks. Stats? Go wild, GL, go wild.
Audi R8 - I don't know. I've seen requests, so I'm throwing it in.
C-Class
Dodge Challenger SRT Demon - average top speed and spectacular acceleration. Handling should be decent, since you can swap the drag tires for more steering-wheel friendly road tires, and nitro should go pretty fast, but still give that little 'oomph.'
D-Class
Toyota GT-86 (or the like) - I know Toyota is currently pulling out of games, but if this is possible, it will probably make the community VERY happy. The car starts off just above the Cayman, and has four stars just like it, but the GT-86 is special. I'd imagine that you could add something like a Rocket Bunny kit on it, and it could go FAST on a lot of tracks. Top speed: you decide, just make it awesome. Acceleration: We're talking about a car that purposely left room for the wildest aftermarket I've ever seen. I think acceleration would start off bad without upgrades, but upon a max out, would totally blow the Challenger 392 away. handling should be fantastic, since the GT-86 takes after the legendary AE86, which was balanced PERFECTLY AND FLAWLESSLY. Nitro should burn at a speed similar to the Lotus Sport 410. This car could become D-Class king, and blueprints should be attainable through a LONG career season for east Asian cars ONLY, like a JDM season. The season could be 50+ races, and end with enough BPs for the GT-86 to get it and star it up ONCE. After the season is over, players get access to a series of LTEs similar to those associated with the Rezvani Beast X, Cadillac Cien, and VLF Force 1 V10. If Toyota is willing to give us this car for A9L, I swear to you, I will send a handwritten thank-you note to both Toyota and you guys. This car can be absolutely BONKERS.
DO NOT ADD DEVEL SIXTEEN - Here's why. People will ask and ask, but the Devel 'has' 1) 5000 horsepower that is not road legal, burns gas extremely fast, and is so far impossible with even the most high-powered hypercars. 2) handling. According to Devel's concept reveal way back at Geneva a few years ago, I was there. I loved the concept, sure, but I knew it wouldn't work. brakes required to stop a car with 5000 bhp at over 300 mph DON'T EXIST. By the time a player got up to 300, they'd either be past the corner, or incapable of slowing down fast enough to even DRIFT the corner. And that's saying something. A9L is actually generous with the speed at which you drift. most drifts in A9L happen at about 130 - 140, IRL, they happen at something like 20 - 60. The Devel Sixteen is not only a bad car for real life, but also a HORRIBLE WASTE OF GAME CODE AND EFFORT, BOTH ON THE PLAYER AND ON GAMELOFT. Caps lock was on so that people got the message. Go ahead and quote me on that.