I'm a racing and performance driving instructor. Been doing that for a little over a year now. I mostly work with karts, but I do some car stuff when I can.
It's not a high paying job. We work on contract mostly, both private and with schools and experience companies. It's almost always a daily/half-daily rate. The daily rate for most instructors usually starts around the $100 mark for bulk contracts (schools and experiences). Standard rate for private gigs is around $500 per day around here for track days and club racing, around half that for karting. I've heard of some coaches price discriminating up to $2,500 per day for things such as Ferrari Challenge.
Right now I have between 2 and 4 days a week of work, but it picks up in the spring for obvious reasons. It can become a 7-day affair, but it is impossible to tell because it's all on call. I might get a day scheduled 2 months in advance, or I might get sent a gig the day before. The job is not physically demanding, but it can be extremely mentally taxing depending on your disposition toward being near or riding with learning drivers who are pushing their envelope and your familiarity with the subject. As you go along it gets easier. You learn about people skills. You have to help people do the most awesome, most difficult thing they've ever done in their lives and everyone needs a different approach to help them keep going. You learn a lot about helping people find their zen thing amidst the chaos. You learn a lot about what you can control and what you can't. There's a lot more of the former than you would expect. You learn how tone and phrasing changes everything, especially when you're sitting in the right seat.
You learn a lot about driving, too. As a driver, I get to see everyone make the mistakes I never made. I get to learn vicariously. Spending a day teaching folks in just as informative as spending a day driving. Maybe more so.
It's exhilarating, and a big adventure. There's a lot of pressure, because you're responsible for safety, their enjoyment, and their learning (in that order). It's a grand way to spend your time.