Akimoto,
I'm going home tomorrow.
I won't buy this necklace. Hope our local store will have more in stock or I'll travel to Europe again till the end of this year.
I'm a little bit sad as neckalce should be my birthday present, but if it's overpriced I can wait
It's not that the D is overpriced per se, it's that it's Tiffany's, so you'll always be paying more than a D VS1 elsewhere.
Like @akimoto , I think the color is an overkill for a stone that size. You will never see the difference between .18ct D or F, and most likely won't even see it between a D and G. But if a high color is symbolic for you, then I understand.
I think Tiffany's makes the nicest bezel I've ever seen, and if it didn't poke me so much, would have a few myself.
Good luck and keep us updated.