Ah, I feel you - I am a car girl, and my daily driver is 8.5 years and at that point where it's feeling noticeably old - little things are breaking or rattling, it's dirty/dinged, etc. Plus my DH is very non-Mustachian -- on our way to the grocery store today, he's telling me it's time to start thinking of what car I want next!
For you, if you are up for the buy-used-fix-up-and-flip, that could be a great option -- MMM once profiled a guy who did that that might give you some inspiration.
For me, the thing that seems to be working (so far) is to convert the cost of the new car into additional months at work. At least, that's what I did today. "Gee, ok, I can buy that car, we can afford it. And then I can tack on another 9 months at work to pay for it." I mean, I like my job, but we are outta here when our youngest goes off to college. I do not want the lure of brightshinynew to F that up for me.
Of course, it probably helps that we also have a Mustang for when the weather is good. :-)