Wich BMW? One of those sketchy ones from sites like modsgaming.ru and others? Those should be best avoided, since they're generally considered to be very low quality.
There is 1 here with custom audio, and as we all know, custom audio is both forgotten by the russian sites and also broken in last update.
i don't have a Renault 5 turbo but the engine has literally no power but when you get higher than 4,000rpm the car makes a tonne of horsepower, is it the turbo? It barely pulls below 2,000rpm
The posts above yours explain why there is no sound... Short story, the Steam update broke it. The only car that seem to have working custom sounds on the new update is SoHigh00's Del Sol.
Please stop bumping old threads. Anyways, repacked version, likely other things are broken. EDIT: Please download the luafix version, otherwise it won't spawn.