Good points - thanks for your comment! I think I agree with you that the in between may become the "worst of both worlds" rather than the "best of both worlds". I will have to keep the number of options low, especially if the number of concurrent players aren't that many but as you say - it'll be easy to see which one is more popular and if there are enough players I may as well keep the modes.
Funny you should mention 50% because today I recorded a slow motion video where I ran it at 25% and it had a certain charm to it (see after the pile up where I drive normally):
You can really try to hit the apex and perfect the lines and if I were to add the "dirty" racing mode it would probably be quite fun an tactical as an alternative.
Great stuff! Thanks for sharing your thoughts :)