As much as I love my Edition 30, there is no way I would swap an S3 for one. I'd rather sink the investment into making the S3 feel more interesting in the corners, which isn't hard to achieve.
Audis are just so much better made. Most people assume it's the same car underneath, with a different badge, but VWs are very noticeably inferior to Audi. SEATs even more inferior still, and Skodas right at the bottom. People buying Skodas thinking they are Audis with a different badge are deluding themselves. Everything is built to a price point.
It's not so much the perceived interior quality, but everything on the Audi is better. Better corrosion resistance, alloy suspension parts instead of steel, better engines, better electrics, better paint, better everything.
The only thing Audis are guilty of is looking boring, in the case of the A3 at least.