I mean it's pretty good so far but you should introduce tire width upgrades and tire pressure tuning because if you have a rear wheel drive vehicle you would prefer wide back tires thinner front tires and low tire pressure for max grip for the rear tires which is what you want

I mean they are pretty basic but might as well be part of the popular vote on the subject so obviously underglow, window tint, carbon fiber parts which could be used for weight reduction,

I think there is more potential in the upgrade shop there are many more engine upgrades out side of the categories you have maybe add block upgrades to add just a bit more power, the flywheel upgrade could be used to give your car lighter weight and more rpms, you also have camshafts, valves, weight reduction, and maybe even manifold

The upgrades are good but you can add more of you wanted like for example in pixel car racer you can either have supercharger or turbo but I've seen proof that you can have both a supercharger and twin turbo at the same time but to make thing more insane I've seen a video of a dude having a four cylinder engine equipped with four turbos that one turbo per piston just something I figured I'd point out and yes please add more garage space