2018 BMW M550 Bulb Size

Decision: This bulb size list aims to identify compatible lamp types for a 2018 BMW M550i xDrive so you can replace bulbs with minimal trial and error. Constraints include model-specific fitment, OEM versus aftermarket differences, and common variations across trim levels, which I note as evidence informing the recommendations. Options and comparison: I list standard bulb codes alongside brief interpretations of their typical uses, comparing original equipment sizing with common aftermarket equivalents and noting limitations where fit or function may differ. Recommendation: use the chart to match part codes, then verify vehicle sockets before purchase. Affiliate disclosure and risks: Some links may be affiliate links that provide a small commission at no extra cost to you; this is stated for transparency and is not intended to influence the evidence-based guidance.