It's weird because the more "realistic" the sound you use as the source for your in game sounds, the more you find people say it's "unrealistic" haha.. I used real sounds for my pack and they were based on how it sounds when you are watching F1 cards in real life, and whilst it was the most popular at the time, a lot of people said they didn't like certain sounds, when they were the actual sounds of an F1 car.
What people expect to hear in a game and "think" is realistic is sometimes different to what is actually a realistic sound, but I'm a purist - the more "real" the better for me. If you could get some good onboard and TV footage for your samples, you should be able to use any decent audio program to shift the pitch to get the correct note for the game and you're sorted..
Let me know if you get some good samples and want some help extracting the correct tones/pitch etc. I don't mind helping - I'd love to see a good 2011 sound pack.
Cheers