This is the BMW M3 GTR sound used in the PS2 Demo (Alpha 124) of NFS Most Wanted, which features a different whine. Not many like it, but I got used to it. In case anyone wants it, here ya go.

Please notice, the acceleration and top speed sounds have some "clicking" sounds at the end. I didn't find it too annoying, but that's just my opinion.

By default it replaces Bank_031 and Bank_032 (these being the sounds used for Alpha, Buffalo, Hotring Racer (A), Hotring Racer (B) and Infernus).

If you want the actual car, check out Hanan-SRB's BMW M3 GTR mod:
https://www.gtainside.com/en/sanandreas/cars/66365-bmw-m3-gtr-e46-2004/

Sound recorded from Need For Speed: Most Wanted (2005)