For rotors check and see if JHM has any possible options. There performance rotors come in all kinds of sizes and they have a really good selection usually cheaper than OEM and they are performance rotors so you can save a good chunk of weight while picking up a better cooling rotor.
if it is a shape/spoke issue, then in theory it could be an offset issue, no? meaning a set of 10mm spacers lets say, might allow the spokes to clear the calipers? usarim told me that their rotors do fit the S6 with the oem calipers (is there a beefier big brake caliper out there? the oem ones are massive).
as for rotors, i thought my C6 ones were massive at 15.2" (at least you could get aftermarket ones for decent price), but yes these are just enormous at 15.7" i believe? ECS has aftermarket ones but they’re actually more than oem ones. the dealer where i bought the car actually replaced the rear rotors/pads and front pads - was really hoping they’d do the rotors as they’re not cheap, anyway, i had requested prior to purchasing for them to put on ceramic pads if they do replace them - i had just installed adams rotors and ceramic pads on the C6 and they felt great, and no dust to boot - yes those oem pads are just terrible with dust. i looked at JHM and they don’t have rotors for the C7 (or much at all), and as noted no one really carries anything besides oem - adams says they’ll make them, but they’ll be more $$ of course. i ran semi-metallics on my C5 and was very happy with them (metal master i think?), good stopping power, less dust than oem and cheap.
You can call it whatever you want, and try whatever wheels you’d like. I’m not saying that those usarim wheels won’t fit - they might indeed. It’s just that the C7 S6 is relatively rare vehicle, and that people often make assumptions that it’s similar to the A6 in these areas, but it’s not.
Again, I won’t run spacers, so I only considered sources I trusted that offered wheels guaranteed (through Discount Tire) to fit. Everything went smoothly for me…
Best of luck to you and please report back how everything goes…
funny, i went back to usarim website and looked at some other wheels, specifically the 18" rotors - for which the website says fits '07-16 S6 - which i know is wrong, so your skepticism is warranted…so unless they can tell me they’ve fitted the 19’s to an S6 with no problem and/or they’ll pay to return the wheels if they don’t fit, i guess i may have to look elsewhere