2020 Audi S4 Bulb Size

Decision: This bulb size chart is intended to help a 2020 Audi S4 owner quickly identify correct lamp types for headlights, fogs, turn signals, and interior lights, reducing guesswork and installation time. I present the list as an observer_analyst, with interpretation of common variations and part numbering based on firsthand inspection and reference data. Constraints and options are summarized so you can compare halogen, HID, and LED choices alongside original equipment sizes. The evidence and limitations of each option are noted, with a brief hypothesis about longevity and brightness trade-offs to guide interpretation without oversimplifying. Recommendation and risks: follow the chart for fitment, verify vehicle specifications before purchase, and be aware of potential CAN-bus errors or legal restrictions for aftermarket LEDs. Affiliate disclaimer: some links may earn me a commission at no extra cost to you, which supports maintaining this reference.