I know the features of the various Vista options (Business, Premium, Ultimate etc.), But NewEgg has some that I don't understand. There is Vista Ultimate upgrade (normal and signature). There is the Premium and Ultimate "TECH SKU" versions which cost more money. I have tried to find out what the "TECH SKU" versions are from NewEgg, but I haven't heard from them. There is no explanation on their Web site that I can find. Does anyone know what the TECH SKU version means--or the difference between the Ultimate and the Ultimate signature? Thank you for any help and info you can provide!