I guess it depends how well you feel you know the sciences. If you feel you are strong in them I would say just use Exam Crackers. Exam crackers also has audio CDs which I found very helpful. They are very clearly written (as opposed to Princeton and Kaplan) and are high yield. If you feel like you need more work with the sciences then consider taking a full MCAT course. Kaplan isn’t very good.
Any questions feel free to ask!
Congrats on going to med school. You will love it!