The 2013 Audi TT RS uses a D1S bulb for both the low-beam and high-beam headlights. The supplied fitment data lists one headlight configuration and does not identify an alternate bulb for projector, non-projector, or other headlight variations, so confirm the existing bulb and housing before ordering.
For additional exterior lighting, the fog lights use H11 bulbs, while the front turn signals use 7507. The rear turn signals are listed as 921, reverse lights use 921, and the brake and tail lights use 7506. The center stop light, daytime running lights, license plate lights, and parking lights are listed as LED units rather than replaceable bulb sizes.
Interior applications include 2825 bulbs for the glove box, interior, map, and trunk lights. The vanity lights use 6418. Check the original bulb marking and connector, particularly for the D1S headlight bulbs, before replacement.