Modification of car stereos is legal. There is no need to report changes to the vehicle management office, and the annual inspection can be successfully passed. Changing the speaker sound is not an exclusive service that only the rich and luxury cars can enjoy. It is a model for solving problems. Since the core selling point of a car is mainly driving use, in addition to the system performance of the car itself, manufacturers will not install customized and powerful equipment, such as car audio systems, due to cost and other reasons. All of the included speakers are the default ones, so they feel effective and the sound is low and unclear. That's why using retrofit speakers solves problems like this. Our musical pursuits come in many varieties. Some people want warm and rich vocals, some want clear and ups and downs of pop melodies, and some want powerful rock music. It is not illegal. The more common car modifications focus on comfort and applicability, mainly audio, reversing radar, lights, tires and other parts. Since factory parts are often removed and replaced with parts with better performance, There was almost no damage to the body. These are modifications that do not affect vehicle performance and do not violate relevant laws. 1. Car audio modification, as the name suggests, is to modify and upgrade the car's audio. Its purpose is to meet the needs of car owners for car music; to allow the audio space in the car to express the "hot" pursuit of music fun with the best sound field performance; 2. Car audio and car audio modifications are also within the scope of legal modifications, and decoration can generally be carried out as long as the modifications are not excessive. By the way, when modifying the electrical components of the audio system, you must entrust a regular and qualified shop to perform the modification. Otherwise, not only will it cause problems such as short circuits in wires, and insurance will not be required, but the consequences will be disastrous. Secondly, after the audio modification, it is necessary to avoid affecting the driver's vision and judgment, without violating safety. 3. When audio modification is made, attention must be paid to circuit problems first. When performing car audio modification and repair, be sure to go to a car modification shop with professional experience. Because unprofessional modification shops are likely to damage the original car circuit during the modification process, not only the sound effect will not be improved, but also the vehicle warranty and a series of after-sales services may be affected. Therefore, when wiring, be sure to wire the power cord, audio wire, and signal wire separately, and ensure shielding and protection between lines.