Not trying to get involved in the argument, but you’re both wrong! Audi rings ie: Audi Beam are the only logo available on an A3 so anything outside of that will look pretty naff. Also to look professional also means that high quality will be needed. None of those examples in this thread have set my pants on fire! In fact all aliexpress or eBay puddle lights are shocking, Iv had them. Only way forward is to spend the cash and get genuine Audi ones. I know you guys will come back and ask why because yours are fine, but if you say that then you haven’t experienced or seen the Audi genuine ones up close.
OP: can’t really help with the sill lights but a google search threw up these below. I think these are correct as they are similar to my Q2 sill lights. They will shine white, so forget the red in this link below!
https://dam.sg/product/audi-genuine-parts-audi-s3-8v-original-door-sill-ambient-light/