
Rear spoiler modification is considered an illegal modification and cannot be registered. The following are the relevant regulations and scope of car modifications: Car Modification Regulations: Car modifications must be carried out in compliance with relevant regulations; otherwise, the vehicle will fail the annual inspection. Therefore, it is advisable for car owners to consult in advance whether the part they intend to modify is illegal before proceeding with the modification. Scope of Car Modifications: The vehicle model, engine model, and frame number cannot be altered, and the body structure must not be damaged. Changing the color of the car, replacing the engine, body, or frame requires inspection of the vehicle. Additionally, a safety technical inspection certificate must be submitted for replacing the engine, body, or frame. Installing windshields, radiators, toolboxes, spare tire racks, front and rear anti-collision devices, or adding interior decorations require a modification registration.

I've modified several cars before, and I was particularly concerned about legal issues when installing OEM spoilers. Based on my experience, it's not a simple matter: First, you need to check local regulations. In China, vehicle modifications must comply with the "Motor Vehicle Safety Technical Inspection Regulations." For example, the height of the spoiler cannot exceed the original design too much, otherwise it may fail the annual inspection. The advantage of OEM spoilers is that they are tested by the manufacturer and are generally safe and legal. However, if the appearance is significantly altered through private modifications, traffic police may consider it illegal and impose fines ranging from a couple hundred to over a thousand yuan. I advise fellow car enthusiasts to first check local DMV regulations and, if possible, keep receipts and OEM certification for the parts. In terms of safety, OEM spoilers can improve stability, but improper installation may lead to increased driving noise or wind resistance. Don't cut corners by going to non-professional shops. After installation, it's best to take photos for documentation to avoid future disputes.

I'm a car enthusiast with over a decade of experience in modifications. Adding OEM spoilers is quite common in our circle. From a technical perspective, OEM parts usually match the vehicle's design and carry low legal risks since they don't alter core performance. However, the legal aspect is a gray area: some regions strictly prohibit any modifications, and even OEM spoilers may violate vehicle appearance regulations if they protrude excessively, making them prone to roadside inspections. Safety can't be overlooked—improper spoilers may increase instability at high speeds. I've handled cases where friends failed annual inspections due to modifications and had to remove them. It's advisable to consult a technician beforehand to check material durability; generally, choose genuine OEM parts and conduct aerodynamic testing. In short, understanding local regulations is key—don’t act impulsively just for aesthetics.

As someone who frequently engages in DIY, I believe adding an OEM rear spoiler requires careful consideration of legal and safety issues. Original equipment parts are designed to meet standards and are generally legal, but if you modify the mounting points or increase the size during installation, it may not comply with safety regulations, leading to illegality. For example, during annual inspections, if the spoiler significantly exceeds the vehicle's body dimensions, the DMV will flag it as a violation. I remind everyone to measure the original vehicle data before modification to ensure the spoiler does not exceed standards; otherwise, fines are minor, but insurance refusal in case of an accident is more troublesome. Keep it simple: purchase OEM parts, have them installed by professionals, and take photos for record-keeping. Avoid random off-brand accessories—they are less durable and pose safety risks.


