Please make sure to post your references. The external dither-aa sorta defeats the point of aa, you definitely have enough colours there.
Looks like a dithered AA of some sort. It's not bad, but it definitely does look a bit unnecessarily jagged.
Bold shapes, lots of care in the AA (though I'm not a fan of "jagged" AA, at least on crisp displays )
But isn't there a problem in the grey lines near the bumper ? They look like they suffered a scaling or something. Sometimes it's better to round to the nearest pixel-friendly angle.
I found the reference he probably used: http://www.speedhunters.com/wp-content/uploads/2009/07/imp15_Mnxg_1.jpg