Like everyone else and their brother, I’ve owned an E30 “back in the day.” Mine was a mint 325is with the nice sport seats in your first photo, it was a fantastic car but definitely not structurally strong like a 911…hardly anything was in those days. Extremely well put together but you could feel it twist when you cranked really hard on the steering wheel. The average driver would never know this but you’re not the average driver.
I also had a 533i sedan with 5-speed manual and that is one of my most missed cars out of dozens owned. I’ve never had anything that was so sweet to cruise at 100+ mph. Back to E30s, for “top dollar” I would only buy exactly what I wanted, which would be a 325is coupe manual with relatively low mileage. Unless you need the AWD for winter driving, it reduces the fun factor by a lot on that car. Any 4-cylinder 318 would be a hard pass, they were just underpowered. Same with convertibles, just extra weight and less stiffness in a car lacking stiffness to start with. Most are trashed and they were always girl’s cars.
Edit: I would consider a manual 4-door with the I-series 6, (not the e-series 2.8, which was a low-revving economy motor). The 4-door E30 had nice proportions, IMO, and I doubt that they drive any differently.