Hello! My name is Adam, I'm from WV, USA where I've been working in Unity for the last 3 years.
In that time I've worked a bit as a tutor and can certainly help you create a flexible racing system that can work for an eventual multiplayer component.
Can you explain a bit about the part your having trouble with? Just making stuff move at all, the shifting mechanics, etc.
Do you have much finished at the moment?
Do you have a list of milestones youd like finished? I can't quite give specific ones at this time, but I believe my budget will be accurate, if anything a bit less depending on what you have finished.
Please let me know if you have any questions,
Adam