Your investment in equipment will be much greater in the automotive world...

That said... do not let that throw you.

You sound like you are starting from no experience either way. Do you know that you will LOVE the automotive business (you can't just like it, if you want to be wildly successful.)

Training in the automotive field is very important. It is also important to market the business effectively. Auto repair is the biggest bargain in the world! The average car today has more electronics than the lunar module! And yet, the average member of the driving public still thinks that the stupidest people should become a technician... That is what they used to do, encourage the lowest in the class to "fix cars." It is not that way anymore! Some of the people with the skill sets to be engineers should be repairing cars. And, sadly, the field does not pay at that level. That is beginning to change.

$4000 is a bare (BARE!) minimum for a professional's hand tools. I will also tell you that many techs have a very inflated idea of what is in their toolbox.

I will probably post some more later, as I need to get back to work...