I have a black Audi and a black Acura MDX and had the same problems as you. I took 2 different routes and both worked well, but it depends on the condition of your car.
On the new MDX, I used SMR for Dark Cars to remove swirls, Klasse AIO to clean and lay down a layer of protection, then ended up with 3 layers of Platinum UPP. I don't know if I needed 3 layers, but it worked great. Car really glows and cleans up real easy. I didn't like the plasticky look of Zaino, but the Platinum I found to be a nice product that darkened the paint a bit and makes the car, well, glow.
On the 97 Audi A8, I had scratches as well as swirls and couldn't get the dang things out with SMR, so I got some 3M Fine Cut Rubbing Compound, put on a wool pad and went at it. At first, it dulled the finish, but then I took the yellow pad and went the SMR route, cranked up to 6. At this point, you could apply the wax, but what I found really made a difference was hand rubbing the Aud with S100 Paint Cleanser. Maybe it was in my head, but I saw a difference. I then tried out Poorboy's EX, a sealant with Carnuba. I applied layer 1, and was happy, but followed up with 2 more and now the car is just a dark, deep, and shiny. I am so impressed with this combo, in the last 2 weeks I did the same SMR, S100 SEPC, Poorboys combo on my neighbors Black VW Turbo Beetle, another dark green BMW X5, and finally a British Racing Green Jaguar XJ8. All turned out great and I couldn't be happier.
In your case, I would try the SMR, the IHG and then top with the Eagle One. However, if your swirls include scratches, I think you may be challenged getting them out with the PC and SMR.
Good luck.
Sam