I have a couple of LaCie drives, including the Porsche slimline 250GB SSD. I wish that they would bring out a 500GB SSD version of that or their Porsche Desktop series. It is the desktop versions that confuse me, LaCie has two different series of the Porsche Desktop unites, both have the same physical dimensions. One is offered in 3, 5 & 5GB version the other in in 3, 4, 5 & 8GB versions. Is there a difference between the two Porsche desktop series?