I dunno I never used massdrop in my life, there is no guarantee I will even get a HD6xx because its all a chance if you will be selected or not.
I don't know if they send invoices if they do then I will be screwed.
Its also not glossy like the HD 600
Massdrop is the absolutely worst seller I have ever seen. So I stick to Amazon
MD is notoriously slow and their customer service is about the worst ever. I don't use them anymore after getting stuck between them and the manufacturer over a couple small things not included in the shipment but specifically mentioned in the drop. The aggravation was not worth the $5 it took to buy the extras outside of the drop but did make the drop price not attractive after adding the $5 back in.
If you need to avoid the taxation the packing Slip sent by MD has no pricing on it, that's what family in the EU use to avoid the import duty and call it a gift, YMMV by country.