I HAVE THE ANSWER FOR YOU!!!!!!!
My last three cars were black, and every time I swear it's the last. I had a 1998 Saleen Mustang convertible that I was the original owner on from 12 miles. It was black and had swirl marks, rock chips and acid rain spots after 6 years. At about 30,000 miles I took it in to get the bumper touched up and told the guy to buff the whole thing out. He told me that he had a guy that would buff it out and Zaino treat it. I had previously bought and applied Zaino products, but applied them myself by hand. He charged me $350 for the treatment and let me tell you, IT WAS AMAZING. My car didn't have one swirl mark, scratch or anything even in direct sunlight. It also felt like the finish was thicker and one year after it was treated IT STILL DID NOT SWIRL MARK. I actually thought about keeping it because it looked brand new. I didn't of course, because I got my dream car.
So now I have a black 2003 SRT that I bought a year ago with 3600 miles and I already have swirl marks out the ass and slight acid rain spots (from the previous owner). I am going to take it to the same guy here in Charlotte, NC and have the same thing done to it. His estimate was around $450 (Viper tax).
Swear to God, my Saleen looked better with six years of driving and then the treatment than it did coming off of the showroom floor, no lie. Do not buy the Zaino stuff online because it doesn't work the same if you apply it by hand. Further, you can't get a nice finish until the swirl marks have been buffed out BY A PROFESSIONAL. You will be thrilled with the results if you find someone who knows what they're doing. I was also surprsed at how big a scratch could be removed by buffing.
I will post some before and after pictures after I get mine done, but it probably won't be for about a month or two. Hope this helps.