Ok, I'm a total hack at Photoshopping. Now that that's out of the way, I realized that the reason the stock 15" wheel covers are so ugly is that they make the wheels look too thick. So, to see what would happen if I painted black the parts of the wheel cover that are too thick, I chopped a nice pic that was posted a while back. Better or worse?..tanking into account the bad chop job.
I see you have a Package IV. You actually have alloys under the wheel covers. I didn't know that at first when I got my IV. Try taking off the plastics wheel covers and going to Toyota (or ebay) - and getting the center caps and in my opinion it looks 100% better - part number 42603-52030. I have a before and after with and without the wheel covers on my photos.