I do now know kaplan premier
07, but I know that these books don't change much over time (IN GENERAL).
My friend has the Kaplan 800
from 07 and I have the 09 edition. They are almost the same (too bad)
The only book I saw real improvement from one edition to another was Manhattan S . Even the OG ones... GMAC only does the minimum required to publish new editions and earn more money (that is, change 30% of its content and repeat the rest... you may see in the back cover that what I am saying is true by reading how many of the "more than 800 exercises" are new)