[Halon]

Not that I have first hand experience, but my perspective is similar to most that I feel like working on other peoples crap all day may kill your motivation to work on your own stuff, which may run it as a hobby. Things I love as a hobby I like to leave as just that, a hobby.

For a profession, I think it's important to do something you enjoy, but also balance it out as something that is in a good market. If you like to do hands on stuff, find a profession where you can still do hands on stuff, but maybe think outside the box a little other than just focusing on cars. Instead of an auto technician, what about say a robotics technician? Excellent in demand field, still hands on, you're working on stuff not covered in slush and salt, and making good money to support your hobby at home.

Not trying to tell you what to do, just throwing some thoughts out there to chew on. Good luck with whatever you choose!