Nah you can get it for a tenner on ebay, there's always one seller taking the piss on amazon, hoping for a gullible one to pass by https://www.amazon.co.uk/gp/offer-listing/B00AMIA4YM I have the soundtrack, taken from the original DVD at highest bitrate, let me know if anyone can make use of it. .
sounds have stages. so a sound you heae in game might be three sounds. if you imagine acceleration being one. idleing at specific revs being another and decelerating might be another stage. Fonseca is the person to speak to on official forums. its my guess he doesn't help anyone outright. its an fmod tutorial you want for inclusion in game, and maybe an rfactor tutorial might do for the sound bites.
If there was a clear step by step I wouldn't have a problem, but like you say the people with knowledge don't want to share it. I make tracks not car sounds, it's not worth all the time and effort to do this just once.
Yup, I would suggest the same., that it would be nice to be done by somebody that has the skills already. How and who will step in, that is another story..
Quickest route would be to let someone who knows what they are doing do it. I could take the time to learn how to do car sounds and then not share any info with the wider audience, that seems how the audio section of the community function.
I don't know how to do it either but just knowing that the sound of an engine varies with rpm and with load you'll need a bunch of samples to make a decent job of it. Did a quick search and found descriptions of developers having separate intake and exhaust samples and mixing them.