The carbon metallic is a nice option. I just saw a few 2015's with the optional Shark Grey inserts and while it is a nice color it conflicts with the front hood, front grill, rear black fascia and both spoilers. They remain carbon metallic. With that being said it adds yet another color to the car and to me is just too much. If the Shark Grey inserts are your choice then the spoilers, front grill and hood vents should all be repainted to match. Cars look best to me with just 2 maybe 3 colors including the interior. For example, I saw a 2015 Velocity Yellow with Shark Grey inserts option, Carbon Metallic spoilers and Kalihari interior, YUCK! From behind it was yellow, grey tail light inserts, black lower fascia and carbon black spoiler and it just had a lot of conflict (4 colors) with no flow. The chrome wheels added yet another color so from the side with the door open you had yellow, chrome, shark grey, carbon metallic and Kalihari. Just my opinion.