@gns121584: I had 3 weeks from my FAR exam until my REG exam, so I was operating on a bit of a constrained timeline. But as you can see below, REG was my best section yet by a decent margin. It helped that I was doing everything on a short timeline, since even nearing my exam date, when I was doing final review the things I had forgotten weren't totally foreign to me. Again, I'm in school and not working so that also contributes to my time.
My personal recommendation would be to limit it to four weeks if you can (not too long and not too short). I went through the MC's once, skipped the supplemental (ran out of time), and then during final review I focused on reworking a few problems from sections I felt needed more attention and then spent the rest of my time rewriting a "cheat sheet" while reviewing my lecture notes. Test day felt fine. I got through the MC's in about 1 hr 45 mins, leaving about 75 mins for sims. The sims weren't too difficult either, but I suppose I felt more prepared than I expected.
Taxes (corporate and personal) are actually only about a third of the exam (including the credits, deductions, adjustments, AMT, etc.). The bulk is the taxation of corporate entities--not so much calculations, but what goes into taxable income, calculation of basis, and then business law. I got a C+ in my tax accounting class (given, I was a terrible student at the time), but have really pulled it together for these exams. It can be done. Good luck!
BEC 86 (08/30/11)
FAR 84 (10/13/11)
REG 88 (11/08/11)
AUD 86 (11/29/11)
Exam prep - Becker self-study