So really... what is EX: Sandstorm? Here are the facts:
Set Size: 53 in Japan, 100 in the US
47 NEW cards were added to the 53 cards in the Japanese ADV2 set to make EX Sandstorm. These cards were actually pulled from Japan's ADV4/EX1 set.
Set Order: 20th set in Japan, 17th set in the US
Release Date: April 18th, 2003 in Japan, September 15th, 2003 in the US.
Players managed to get a sneak peek at Sandstorm in various Pre-release tournaments on September 6th, 2003.
We're starting to see more and more old skool Pokémon being released, as well as the stats for them. For example, Cyndiquil is not in Ruby/Sapphire (through the normal progression of the game that is), yet it's numbered in the 300's. So... for those who don't own a GameShark, this is an interesting development.
As mentioned above, this set had 47 cards added to it on top of the 53 cards from the Japanese set. These 47 cards were pulled from Japan's ADV4/EX1... but don't expect to see them again in the English release of ADV4/EX1.
EX Sandstorm Prerelease Draft Checklist
EX Sandstorm Pack
The symbol for EX: Sandstorm is a Claw and Root Fossil.