There are a few things to consider before giving up on OEM parts
1) Reliability may be reduced
Performance modifications often result in reduced reliability, especially if you change engine parts (including intake and exhaust).
In some cases, producing more power than the vehicle can handle can put you at risk of damaging other parts. These parts may be easy to repair, such as engine mounts or transmission mounts, but they may also be internal engine parts such as piston rings or connecting rod bearings.
Some vehicles will require a piggyback ECU or an aftermarket tune if you are replacing parts that may affect the air-fuel ratio. Aftermarket tuning can usually only be done by professional tuners. Modifying hard parts without the associated software can be disastrous and quickly lead to engine failure.
If the vehicle you want to modify is your everyday car, you should think twice before tinkering with the engine too much. If you don’t have a car, repairing or replacing the engine can be time-consuming.
2) They are often expensive
Apart from simple cosmetic changes, high-end modifications are usually expensive. Expect to pay at least $1,000 to significantly modify the performance of your car. There are many people who have spent five or even six figures on the conversions seen on YouTube.
Funding aftermarket modifications is usually not a good idea. If you don’t have the funds to buy the parts outright (and have spares in case something goes wrong), it may be best to save some money to stretch your budget.
3) Some modifications are illegal
Depending on where you live, some modifications to your vehicle may be illegal, or may only be legal for off-road use. For example, six-point seat belts are an alternative to standard seat belts, but are often not DOT approved. They are suitable for racing and are very safe, but are not legal for use on public roads.
In New Mexico, all side windows can be tinted up to 20%, including the front windows. In many other states, the minimum allowable windshield tint is 35%.
Subsequent engine modifications are illegal in California unless approved by the California Air Resources Board (CARB). This eliminates many options that are perfectly legal in other states.
Always check local laws before modifying your car. If you are pulled over, you may receive a ticket requiring you to return the modifications to their original state.