When looking to modify your car, you need to take into consideration what you want for the car; either functional or cosmetic/aesthetic. If you are going for functional modifications, you are wanting to put or replace parts on the car that have an actual reason or purpose for being there. These mods are to benefit or to allow the car to perform better. But if you are going for cosmetic mods, it’s just that, to look eye-catching and add personality to your car. So this would be splitters, wings, under-glow, paint color (body and rims), and widebody kits.
A list of functional modifications and their purpose (benefits):
Upgraded exhaust system: it gives you more power by reducing back pressure, can improve your fuel economy by regulates how much gas is being “exhausted,” and changes the sound that comes out of the exhaust (which is more personal preference than functionality).
Upgraded brakes: it gives you a quicker stop time by the pads having a lot more traction on the rotors, improves the durability of the whole braking system by it allowing more airflow to cool down the heat created by friction of the pads, rotors, and brake lines; meaning that you don’t have to replace them as often as you would with the factory brakes.
Upgraded Tires and Rims: Tires; it gives you more traction (depending on which tire tread you get and what conditions you are driving in) by the tread creating less friction between the road and tire (meaning you have less wheel spin) and it gives you greater stopping ability because tire tread sticks to the road better than factory tires. It can also be aesthetically pleasing if you get tires with white lettering on them (it makes the car pop more). Rims; about the only functional benefit of upgraded rims are, it saves weight if you get a lighter material of rim (making the car faster).
Upgraded suspension system: if you go with coil-overs (looks like a coil), you get a better/more comfortable ride when driving, allows you to lower your car from the factory set ride height (more aerodynamic), and are usually more durable when they are put on a lighter car. If you have a heavier duty vehicle you would want to go with a rigid axle suspension system, this is made for taking on more weight when loaded up; basically for trucks.
Upgraded fuel system: this usually means getting a flex fuel kit (or a totally different fuel system if you are swapping the motor out), this allows you to get more efficiency out of your motor by burning whatever proportion of mixture is in its combustion chamber. If you fill up with a premium gas (91 octane or higher), you will get better engine performance, same or better fuel efficiency of 87 octane (regular gas), and less wear and tear on the engine, but at the cost of higher price per gallon, it’s also just as bad for the environment as regular gas. If you fill up with E-85 (Ethanol=corn syrup made for vehicles), you will get better engine performance, a cheaper price per gallon, and less environmental harm, but at the cost of less fuel efficiency, possibility of engine damage because it absorbs dirt easily, and less of a chance that a gas station will have that type of fuel.
Sources:
“4 Reasons to Upgrade Your Exhaust System.” American Muffler, 13 Jan. 2016, http://www.browardcountymufflers.com/4-reasons-upgrade-exhaust-system/.
“Flex Fuel Vehicles: Advantages and Disadvantages.” CarsDirect, http://www.carsdirect.com/green-cars/flex-fuel-vehicles-advantages-and-disadvantages.
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