RE: What Salary needed to afford Challenger
In the "olden" days when people went for mortgages. Lenders based a lot of peoples ability to handle the mortgage payments by figuring 1 week salary for the mortgage payment, 3 weeks of salary for everything else. Of course lots of changed since that way of figuring was done.. but... an easy way of doing that for a car loan could be applied the same. In your situation living at home you could go a bit further maybe 1-1/2 weeks salary= car payment.
Worse thing to do is work for a car or make everything center around a car loan. What I mean by this is, don't over extend yourself where you cannot buy anything because you are held captive to a car loan. Be able to put money away after all your bills are paid. I know many who rely on overtime to make payments. When overtime is pulled they struggle and have to seek 2nd jobs. It's not wise to get yourself into a situation like this. I think if you apply the method I mentioned you should be ok. The trick is to stay disciplined in your payments. There may be a time you will want to move out and you'll need money to do that. If you pour a huge chunk of change into a car loan you'll end up screwing yourself out of things down the road. Hope this brief synopsis helps.