I'm not being critical here, just want to make sure everyone understands - auto paint, especially metallic paint, is virtually impossible to get an exact match on. for jobs larger than rock chips on bumpers, if you have a sharp eye for detail, want a perfect match and have the cash, I would advise against DIY... unless of course you know what you're doing.
the body shop I took my last car to refuses to do spot-repair. they paint the entire panel and feather the edges to the connecting panels so you can't see the difference. I can't tell you how many bumpers I look at where I can clearly see the difference in the shade of the body, when someone brings their car post-fender bender to the lowest bidder instead of a quality shop. I also know a guy who had a body kit put on a relatively new 350z. Paid thousands for a beautiful kit, waited months for it to arrive from China, and told the shop to paint it the factory color. the problem is, paint fades, so a match to factory paint doesn't match the car. I can clearly see the difference between the body kit and the car, the car being several shades lighter than the kit. I don't have the heart to tell him though; ignorance is bliss.
now if you don't have the cash or the eye for detail, or are color blind, drive entirely at night, or your objective is simply to make it look a lot better, then go for it. 98% of the population will probably never notice. but it sounds like some of you aren't aware of this, and if you care enough to spend time on this forum, chances are good you care enough to want an exact match.