Which of the following could potentially be excluded from coverage due to vehicle modifications?

The correct answer focuses on modified performance parts, which can potentially lead to exclusions in coverage under a personal auto policy. Insurance companies often have specific guidelines regarding vehicle modifications, particularly those that significantly enhance performance, such as upgraded engines or suspension systems. These modifications can increase the risk associated with the vehicle, which is a key consideration for insurers. Therefore, if a vehicle is modified in a way that affects its performance, it might not be covered under the policy, especially if the modifications weren't disclosed to the insurer.

In contrast, standard repairs, routine maintenance, and minor cosmetic changes typically do not pose a significant risk to the insurer. Standard repairs and routine maintenance are expected actions that keep a vehicle in good working condition and are covered under a personal auto policy. Minor cosmetic changes usually don't affect the vehicle's integrity or performance and therefore do not usually result in exclusions. This helps to highlight the distinction between safety-related modifications and enhancements that significantly change a vehicle's risk profile.