I was waiting for someone to bring up Dave Ramsey.
I somewhat followed his advice. I drove my 99 Jeep Grand Cherokee for 11 years...over 6 years without a car payment. I took 1/2 of the money I was spending on payments and paid myself. Then last month when the Jeep was becoming unprofitable to drive, I sold it for $4k and added that to my savings to pay for my 2010 F-150. I love no car payments.
And now I'm putting more money away: 1/2 of what the original Jeep payments were and the difference in what payments would have been on the F-150. It just sucks that interest rates are so damn low right now.
Now you're making me laugh: you plan on having an American made car for a long time.
You'll be happy if it's still running properly when the final payment is made.
In all seriousness, at your age you should not be spending $20K on a vehicle. Not that you can't, but I'd bet just about anything, before the car is paid off you'll have a family (whether on purpose or accidentally
) and then you won't be able to afford the car OR will have to trade it in for a minivan.