Stoked on this livery and (for the moment) drove it to 1st in JRC Historic in Sweden event which I chalk up to your livery since I rarely take the S1 out and when I do it's usually... not pretty. Since you welcome feedback and suggestions though, as a model builder obsessed with details there are a few I notice which are different from Hanna's. I don't know how to do liveries and suspect some of this is due to limitations of what can be modded but not which parts so forgive me for anything that sounds dumb or is off limits for alteration.
The aero-fin strips on the fender and sides of the wing should be black
Front grill/clip should be white with black Audi logo
Audi logo on hood should be a maroon color
1 on the door a bit smaller
QUATTRO on rear fenders a bit smaller
CASTROL on front fenders aligned with road vs hood-line
Audi Sport be aligns with road too
Bosch Fuel Injection slightly smaller
Michelin on air dam should sort of align with bumper's curve
That said, even as is if nothing changes it's still proudly my default livery for this car now and greatly appreciate the effort you've put into it already.