I work as a tutor and SAT instructor, and I have to say that the above posters are absolutely correct. Above a 2300 really anything goes. Getting exactly one question wrong can be worth 20, 10, or zero points off of a perfect score, depending on that particular test's curve and which section you are missing a question in. Pure luck right there. It's almost impossible to guarantee improvement with studying and practice beyond 2300 for this reason. The best thing you can do is study the problems you get wrong and not just understand that problem, but seek out problems that test the same concept until you can do them in your sleep. Then, on the test, double-check everything. If you're scoring that high, you are probably finishing the sections with plenty of time to spare. Use it all.