I've always thought individual paint was just an exclusive shade of color per model.
Maybe I'm wrong but I suspect the quality of paint is same.
2013 X5 35i Premium, Space Gray, Cinnamon Brown Leather, Dark Bamboo wood trim, Conv. Pkg, CWP, Multi-contour seats, Running board, BMW App. Space saver tire.
2010 535i - Deep Sea Blue w/ NBD Leather, Bamboo Anthracite WT, Sport Auto Trans w/ Paddle shifter, Sports Pkg, PP, CWP, Nav, HD Radio, Ipod.
2007 525i - Black Sapphire Metallic, Black Nevada Leather, Premium package, CWP, 6MT.