For the 2017 Audi S5, both the low-beam and high-beam headlights use D3S bulbs. The supplied fitment data does not list a projector or non-projector headlight distinction, so confirm the original bulb and headlamp assembly before ordering.
Other notable exterior lighting includes LED fog lights, LED daytime running lights, LED parking lights, and LED front and rear side markers. The front turn signal uses a 64132 bulb, while the reverse light uses a 921 bulb. The brake, center stop, tail, rear turn signal, and license plate lights are listed as LED.
For interior replacements, the dome light may use either 6411 or 6428. Map, reading, glove-box, trunk, and general interior lighting may use 2825 or 98, while the vanity light uses 6418. Check the existing bulb where more than one size is listed.