Just to add my own experience, I'm currently waiting for a 2017 S3 Prestige as a factory order.
I've done a lot of research on this topic and I'm starting to suspect that Audi have no clue what they're talking about when they say Homelink interferes with the Adaptive Cruise Control feature from the Prestige package.
What I found suggest that in the past (period not clearly defined, but seems to be more than a few years ago), Homelink did indeed interfere with adaptive cruise, but not anymore as the new Homelink unit that can be installed is a standalone unit that doesn't interfere and only requires power and ground connections to be functional. That, combined with the fact that several owners have installed Homelink themselves with no visible negative effect, suggest that Audi staff are still using older information and aren't aware that their Homelink unit is now compatible with the Prestige model.
I debated this repeatedly with my dealer and they always come back saying Homelink isn't an option with the Prestige package as it interferes with Adaptive Cruise.
Every time I insist they seem to check with a different department (distributor, the port, the factory, technical service, etc...) but the answer is always the same so I believe the wrong information must be in some Audi employee manual or guideline or something like that, which hasn't been updated with the correct information. Unfortunately, I'm unable to get them to add the Homelink option as they keep saying it's incompatible and not offered with the Prestige model.
They kept saying this even after I emailed them a PDF of a sticker from a car from another dealer (from a different state) which was a 2017 S3 Prestige
with Homelink (it says so on the sticker and I called the dealer to confirm). I even contacted that other dealer who told me that:
"Homelink is a port installed option and it is approved and on our factory order list. It doesn't get installed until it hits the port in the US however. Whatever the other dealer told about interfering with adaptive cruise is incorrect otherwise Audi wouldn't have that option available for a Prestige model. Since it's an original Audi part and not an aftermarket it is all under warranty and it does not cause any problems or interference."
Unfortunately, they still wouldn't budge even after relaying this information to my dealer and asking them to explain how that other dealer was able to get Homelink installed on a S3 Prestige (that other dealer
had the car in their lot, so it wasn't not just a case where the dealer promises something then informs you later that it isn't possible after all).
Anyway, I just wanted to share this info with this forum. As for me, in a few weeks I'll end up with my S3 Prestige without Homelink and I'll have to order the part separately and install it myself. At this rate, even after I install it and show it to my dealer they'll probably still say it's impossible.