My choice is the regular GT w/. fog lights.
Of the ones that you ask, I prefer the CS. Because the BOSS one looks like someone stole the fog lights, and just the holes where covered
2011 Mustang GT Premium, Brembo, 3.73 & Std. transmission, Steeda Sport springs & KONI STRT. GT500 strut mounts, 275/40R19 Michelin Pilot Super Sport, HAWK HPS + ATE DOT 4, Rear CS style pedestal spoiler. Eleanor style side scoops, "C" style side decals, Black AM BOSS style roof vinyl, black hood custom vinyl & Black pony.