My opinion:
1. I don't believe purchases should be made based on income. First, buy only what you need (ie, just a car, any car to get from A to B). Second, anything beyond "need" (ie, nice car instead of the minimum) should be reflective of your net worth, not your income. That's just my opinion. I have seen far too many people I know personally go up and down over the years, some years living it up and other years barely scraping by. Any time between up and downs they incur losses they would't have otherwise were they able to keep whatever it is that they buy. If you buy based on need and net worth, you should be able to keep whatever you buy, no matter what happens. If you buy on income, once that income goes away, so does all your stuff.
Unfortunately if most people followed this they would live considerably below how they "want" to live, and it seems a lot of people cannot handle that. When I was young I spent based on my income. I never experienced a setback, but as I got older and saw what was happening to others and I wised up. Now instead of feeling like life is boring or crappy if I don't have a new BMW every two years, I try to remind myself daily to be thankful that I am employed and my family has food and shelter and health. That's all that should really matter in the end.
2. I always finance cars. Its just about the very cheapest money you can borrow, and I'd rather invest my cash than drop it on a car and make money on the spread.
I am not buying a $60k tesla because my net worth justifies it. Not that my net worth is bad, it is more that I have annual targets I want to meet and spending that money on a car screws them up. But, there are qualitative reasons for moving forward with the purchase anyway. I figure you have to allow yourself something, your life doesn't have to be 100% bean counting. I already have a cheap, paid off car that works. I am only buying a Model Y because it is wholly, dramatically different than all cars have been in the last century. I want throw my hat in on this new experiment.