some people would say you’ll need to roto with mocha then set the transfer mode to screen to let the highlights and reflections through.
that’s about 20 min for every 10 sec of footage depending on how fast you click your mouse.
But if the footage isn’t washed out and the car isn’t pure white, you can crank up the saturation channel in color finesse and using a garbage matte, you’ll be able to do a simple secondary color correction in color finesse in an adjustment layer set as screen. Also, if that doesn’t work, you can try my highlight blow out fixer that restores missing highlights and its saturation protect mode can act as a stenciled white track matte which greatly decreases roto time in mocha.
https://www.megaupload.com/?d=7T8L00DR
The only true guarantee is how well the video was shot.
https://technicolorsoftware.hostzi.com/