I think you don't know much about the grey market.
I'm talking about the grey market where an intermediary buys the watch in an official Tag Heuer store but with a huge discount. Then I buy the watch from this intermediary (an official company) with a big discount.
I have always full Tag Heuer warranty on grey market + an invoice from the intermediary's compagny.
Warranty card activated from official Tag Heuer dealer.
With official Tag Heuer shop : max -10%
Tag Heuer retailer : max 20%
Grey market : -25% -> -35%
Since 2002 :
I bought 8 Tag Heuer in official shops.
And 39 Tag Heuer by grey market. Always with warranty (2 years).
Last month, I bought my Carrera Heuer 02 with 30% of discount... and my Aquaracer 300m with 32% of discount.
Warranty cards OK.
Another well-known site where many of us have been buying from them for several years (I bought Rolex, Tudor and Tag Heuer) :
http://www.mallofthewatch.com/fr/categorie-produit/tag-heuer-fr/