Congrats, it is a great feeling. I did the same thing a few cars ago and have just kept an eye on what the one that I have is worth and the car fund. Unless I can trade and pay cash for the diffference, I do not trade.
It does sting seeing that account drained all at once!
Word of advice, take the $800 you are saving every month and put $500 of it in to a seperate savings account and get on the same plan. If you do that every month, it is just like the 401k at work, you cannot spend what you cannot see or what you consider "off limits". That is how we view the car fund "off limits" for every purpose but buying a new car.
I just traded my 07 Denali and bought a 04 Suburban and got a bunch of money back, went right in to the car fund. I am preparing the account to trade the Mustang GT in for a new 2011 Mustang so that I can roll in the 5.0 blasting my Vanilla Ice!! I can see my dumb ass doing it right now.