Best SAT prep book/course?

Does anyone have any suggestions for the best SAT prep for high scorers? I took the (new redesigned) pSAT in October with no preparation and scored a little over 1400. I know I can improve my score, however I’m not really sure how I should prepare. I’ve taken a look at quite a few books and online courses so far, however I don’t want to spend a ton of money on a book or course that is mostly basic concept review. I really want to delve into the strategies of the SAT and the harder, more abstract questions.

Anyone have any experience or suggestions?

I’d link your CollegeBoard account to Khan Academy to get personalized practice. I don’t think you need to spend money on prep books or classes.

Khan Academy is good because the questions are written by the CollegeBoard so its really direct practice.