Nice car and good job on the conversion. You asked for requests for other versions and here is one: Please make the legendary 325is Evo. It was a homologation special for Group N racing in South Africa in the 90's. It had a 2.7 Alpina block with BMW 2.5 head (larger valves) , Alpina 276 deg cam, alloy bonnet, fenders, boot lid, doors, Mtech-2 bodykit with brake vents instead of foglamps, LSD, M3 front suspension, M3 brakes and BBS wheels plus all the extras of the luxury spec 325i. More info:
https://www.carmag.co.za/news-blog/from-the-archives-bmw-325is/
2) That's a 4 cylinder sound (S14B23 if I'm not mistaken) and this is the M50B25. Completely different engines and the sound would be nowhere near as accurate. This sound was compared with real life sounds and is quite close.
3) Don't really see how you could think that honestly, please explain.
4) Ever looked at any Kunos or modded car? It's to simulate the drag of the body, otherwise you'd be able to go 5000mph if you give it enough gearing and power.