The difference is that the Maximum Drive should not have the engraved "W" on the button and the Eternal Memory should have the metallic blue pin instead of silver. Replacement parts mentioned are planned to be shipped by June, 2014. The website didn't mention though if the offered replacement program is applicable to markets outside the Japan.
The Lost Driver was released last February 2014 for 9,450 yen. The Lost Driver uses a leather strap that brings improvement on the texture and durability while on the waist. It can fit waist sizes from 70 to 100cm and is inclusive of the Eternal and Skull memories.