I've taken the test twice already. I'm retaking it next month. Based on my experience, Kaplan QR subject tests don't cover all the meterial you need to practice for the actual test. For example, Kaplan doesn't cover much of the Trig or geometry or even probability problems. You should review topscore and destroyer as a supplement to Kaplan. Also practice the math section of ACT, GRE and other standardized exam. I hope that helps.
ps. Nazafarin, are u persian?