Some thoughts I had today, regarding ending up going a full class below of what I was initially aiming at (RS3, CLA45s etc.):
In hindsight, I'm actually baffled that I didn't have the S3, Golf R or M135i etc. on my radar.
Of course, for someone used to modern performance vehicles, an RS3 or M2 (probably with upgrades) would be at the bottom end of what's just remotely acceptable, but let's face it: After two decades of VW/BMW Family Diesel SUVs, Smarts, Opel compact vans and even a crappy 90s Chevy Blazer, 0-60 mph in 4.4 sec. of the S3 is plenty of kazoom!
The stupid grin I put on during the test drive is still decorating my mug, even though it's several hours in the past.
Oh, and I also realized another thing: Just because a car is based on the same platform as a compact car doesn't necessarily mean it's also compact: The CLA is in fact mid-sized and significantly larger than the A-class. In real life, it appears very compact, but it actually isn't (I also was unaware that the A-class sedan, indeed compact, is not the same as a CLA
).
So after all, I'm really happy with my choice. The A3 8V platform has the exact size I had in mind.