I've had some SGM paintwork done and if your picky like me...good luck...lol. I've had my hood, deck lid, spoiler, gfx and various other things painted twice now and neither one is a winner.
The first job was done by my dealership with the assistance of two local PPG reps and it sucked. I got a refund from the dealership and took it to a highly recommended custom car painter that charged me more than most pay to have a whole car painted. It took him months of paint mixing...using both PPG and DuPont brand paints. (DuPont paint which is what they use at the factory was a terrible match..so don't even waste your money on that)
And once again...the custom car painter worked with several PPG reps and eventually...against their recommendations...applied the paint as a candy process layering the metallic in and over the SGM in a glaze to give it the same factory depth and sparkle. This was a huge success over the dull, flat, dark paint job that my dealership applied (and I made them paint it 3 times...lol) But the color is still a bit off...just lighter this time.
The SGM is so hard to match that the PPG rep told me that almost all SGM damage claims are resulting in a complete repaint. And they insist that the SGM paint must be blended to achieve a match. But I haven't seen a good match yet and I've driven hundreds of miles to see what people claimed were perfect matches just to be disappointed and happy to have what I do. So I refuse to let any painter overspray some crappy SGM substitute all over my car just so they can be happy.
The guy that painted my car the second time...which was just done in August...still has my original deck lid and is working on another match. But he did admit to me that matching SGM is the most difficult paint task he's ever attempted...lol.
And if your interested...here's two threads concerning matching SGM paint that I started last year after my dealership failed so miserably.
If you care to discuss any of this more in depth...just drop me a pm. Hope I haven't scared the crap out of you...lol.