The blue book and subject tests are pretty much all you need but you will want to supplement those with other review materials.
Other stuff you get with the kaplan course is their flashcards (these are useful), a lesson book that you are supposed to fill out while listening to online lectures (waste), review notes book (same as blue book but its white), workshops and workshop quizes (ok), 2 full length tests + midterms (useful).
I have all their workshops/workshop quizes (pdf), 2 full length tests and midterm with answers (pdf), subject tests all saved to disc which I will be selling along with their books/flashcards later on.