Numbers go up, car go brrrr, game is fun.  Very clean in general, and has sounds that don't get annoying when you spam buttons. The background music is a little repetitive, but not annoying.

Most of my critiques revolve around visibility of information. I feel like in idle / incremental games, information is king:

- During the early game, I was really wishing for a way to see the boost meter while not in the car view.  Obviously, this was solved later on, but perhaps this should be a default feature, not an unlock.  Maybe the upgrade permanently activates the boost, but allows you to OVERBOOST into a purple bar instead of green.

- I was sleeping on Acceleration for a long time, because it wasn't clear HOW MUCH faster cars would accelerate, plus it came with an active downside of increased fuel consumption.  In an incremental game, I really do not want the numbers to go DOWN!  Number only go up.  Always up.  Brrrrrrrrrrt.  Just remove the fuel consumption increase, honestly.  It's realistic, but it feels bad.  I wouldn't have realized it was missing if it had never existed!

- Until mid game when I unlocked the Boost upgrade, I had no idea what Boost actually did.  I was wondering if it makes cars go... faster?  Run out of gas faster?  Accelerate faster?  I ignored boost upgrades for a lot of early game because of this, because the impact wasn't obvious.

- I would love to see a preview of what the next major upgrades do, like the prestige and boost upgrades. It feels a little weird to fork over $50,000 for ???.  Usually I was buying those things last, just to presumably get more car unlocks available.  But I might have prioritized them if I knew they unlocked entirely new, very powerful features!

- Visibility on the base trophies a car earns.  I'm pretty sure these were different?  There's a bunch of multipliers in different places like each finish line and individual car multipliers, but it was hard to tell which car to prioritize without any stats on the proportion of income from each car, or a way to figure it out myself.  The little popups when crossing lines were way too small/quick to rely on here.

- Holding shift to buy a stack of upgrades is great, but show me the price of the full stack I'm about to buy! I'd rather not be able to buy any of the stack at all but know its cost (that I can't afford), rather than buy half a stack that it turns out I can't afford all of.  You can always purchase individual upgrades if you want to go as far as possible, given that you can see the full stack isn't in your price range.

And finally, the only feedback not related to information visibility--give a final upgrade to WIN!  I need to feel a sense of closure after clicking so many buttons :)

Overall, great game!  I don't take the time to give detailed feedback unless the game is cool, so great work!