[M5 Dream]

Hi everyone! New to this forum so hopefully this finds its way. Getting ready to order a 2013 M5 for Euro Delivery, and I'm not sure which interior to order. I am ordering a Singapore Grey exterior. I notice the Graphite/Black Extended Merino Leather option is a $5k upgrade. Is that much different than the Black/Black Merino Leather (no extra cost) or Black Full Merino Leather ($3,500)???? Hard to decide when I can't see/touch/feel. Advice??? Also open to Silverstone II Full Merino. Thanks!