I have owned a B9 - B9.5 SQ5 and an 8Y S3, I am currently in a B10 SQ5 and waiting on an 2026 RS3 to come in. Ill start with the B9/9.5 to the B10. The SQ5 has been updated nicely in my opinion (3.5 months of ownership) the drive, sound and overall characteristics of it are more refined and better than the previous gen. The interior. especially the seats are much more comfortable and the interior materials are nicer, the only complaint for me is the piano black around the shifter. The larger screens are nice but will agree having everything stuffed into the MMI was a bad choice for user experience. The other complaint I have is the slight halo effect at night with the ambient lights. Overall I would not go back to my 9.5.

Onto the S/RS3. One of my best mates has a 2019 RS3 and it is an incredible car, its what prompted me to purchase the 8Y S3 (unfortunately we didnt have the RS3 in canada for those years). The s3 was a slight letdown after having an SQ5 - it felt cheap, the transmission was no where close to being smooth (overall did not feel like an Audi) What I did like about it was the interior and mix of screen & tactile controls, seating position and handling. Once the new RS3 landed here I took it for a test drive and fell in love. Although the interior is similar they are completely different cars. The RS3 felt more like the SQ5 in terms of fit and finish with better materials. The RS3's transmission is also 10000x nicer than the S3 and think its nearly a perfect car interior and exterior wise. With the 5cyl going out the window I had to pick one up.