Choosing between a 2014 507 Edtion C63 vs 2015 C63

Hi All,Im looking at purchasing either a 2014 C63 507 Edition or a 2015 C63 towards the end of the year but i cant decide which one to go for.I much prefer the exterior of the 507 but prefer the interior of the 2015. Theres also the fact that the 507 is a true Naturally Aspirated V8 whereas the 2015 is a bi-turbo with 38 less bhp.What are the opinions of those fortunate enough to have owned / driven both? Does the Bi-Turbo sound as good as the NA?Cheers! via /r/cars http://ift.tt/2rUoexw