I've used the Unsharp Mask and another little tip, it's really easy: make a new level and with the brush tool make a smooth white dot in 9px size... then scale it orizontally (enlarge it) an vertically (compress it). Then just rotate the faded line you make in order to fit the car lines (where you have highlights) and play with opacity to making a perfect result (you can try also changing the level properties to "overlay").
Oh, I see... so the point here is I need to play more with level and the right blending mode. You see, I usually choose blending mode 'screen' instead of 'overlay' and just play with the opacity without giving attention to level.
Thanks a lot for the advice... I'll try this advice of yours for my next rebrushed car.