Pretty nice write up, you said it yourself, you are comparing the 5 series to the model 3, I think a better comparison would be Vs a 3 series. My wife has a 2014 328i luxury and Technology packages and and I have a RWD/LR/PUP/EAP/FSD June 2018 build.
Performance: the 328i is quite strong for a 4 cylinder turbo charged, we love the power on this car. BUT of course it is nothing compared against the instant torque of the electric drive. Still both are pretty enjoyable rides.
Ride: I have to say that the 328i is a smoother ride, because of the luxury package. The slightly stiffer ride on my 3 series is not something that bothers me at all.
Interior build: on both cars is supreme, both cars to me look gorgeous on their own way. I have to say that after owning the simplistic model 3 cars with knobs and switches are starting to look cluttered to me.
Infotaiment: On this the 328i SMOKES the tesla. Navigation and sound are superior on Tesla that is it. The bluetooth controls on the BMW are way better, the smaller screen splits to show you navigation and a large display of the artwork of what is playing on your phone, you can also navigate through your playlists and select a playlist or a specific song. also you can shuffle the contents of the playlist you are playing. you can FFW and RWD through the song that is currently playing. Sirius XM is available in the BMW, we subscribe to it and is great in roadtrips. The dependency to cell phone signal on the tesla is a limitation if you travel to areas where signal is patchy, I knew of this in advance so I downloaded a playlist to my phone for our last roadtrip. On the 328i you can also preview text messages from your phone, oh and if you plug in your phone to the car, you get a built in interface to Spotify (I hope if there is an exclusivity contract with slacker that it comes to an end SOON!). We have a kia sportage in the family and it has Carplay, don't get me going on that is being a even better interface!.
Comfort: both my wife and I are short, so the seats on both cars are very comfortable We have done long roadtrips on both cars and never felt tired from sitting down. A big plus for my wife is that she does not have to push the seat too far forward to reach the pedals ending up too close to the steering wheel, this was a problem in my 2009 Mini Cooper.
The HUD I have to agree it would be nice to have in the model 3, I really like it on the 328i.
The 328i has a moonroof, the model 3 has the whole sky over your head for you to enjoy
is like driving a convertible with Air Conditioning or Heater!
Both cars have auto dimming mirrors, which is excellent when a teenager with a supped up Civic with misaligned Halogen headlamps gets behind you, or the usual redneck in a monster truck.
I guess that's all I can think of mentioning about my experience on both our cars. i would say it would be more fair to compare a 2019 330i Vs the current 3 series.