I think what jones (and others) are trying to point out is that if you have a lump some of money at that age it can be invested for a better return than to spend it on a depreciating liability. When you buy a new car (no matter the price) it will depreciate as soon as you drive it off the lot. You buy a brand new Fit for 15k this year, 6 months down the road you sell it for whatever reason and you can only sell it for 12k. In 6 months you lost 3,000$, whereas if you woulve invested that money, even in simple CD's in 6 months you would have MADE a more money, depending on the percentage of the CD. Now Cash Deposits are not the best way to invest money Im just taking that as an example. Even if you were to simply save this money and put it as a downpayment on your house that you will inevitably buy in the next few years if will still pull a great return than buying a brand new car.
This post started out asking for opinions about how to buy a new car thats why I never asked "why are you spending it on a new car" hell man its your money do what ever you want with it. But since you opened the door by saying "Now unless you have any real factual knowledge that will actually help me through out my life" this is the answer you will get.
Hell if you really think your young family is in that much of a bind that you NEED a brand new car then go for it, but dont look at it as an asset because its definitly a liability.