A simple upgrade you can do to make your car a better performer and more enjoyable to drive is to upgrade your brake pads. A better brake pad works in a number of ways to increase your stopping power. Jason Fenske from Engineering Explained is here to explain it all.
The gist is that with a better brake pad comes with material better suited for what you're looking to do. If that means running your car hard, you're going to need a pad that can perform consistently. This is more difficult than it sounds, because when you brake hard for longer periods of time, you increase the amount of heat you're putting into the brakes, and more heat will lead to fading.
A proper performance brake pad helps combat this issue by having a larger operating range with respect to temperatures created by all that friction. One easy way to accomplish this is to simply go with a larger pad.
Some brake pads work great in the cold, while others need plenty of heat to start working but once they do they're like boat anchors.
Choosing the right pads depends on what you want to accomplish with your car. Do your research. Upgrade your pads appropriately. And enjoy your machine even more.
Then go ahead and upgrade your brake lines next. That's right...it never ends.