No do not study any of the performance stuff out of the ATP. Here is what I did and I made an 88 back in december. A guy posted a really really good gouge at aviationinterviews giving as many test questions as he could remember. Study that and know it cold! Go through your ATP book and study the regs (121 regs) although my particular test didn't have many regs others did. Study the flight operations chapter in the ATP. There is tons of questions that come from that section. The aerodymanics chapter of the ATP is a must, especially the VMC questions. ALso somewhere in the ATP there are some engine performance questions. That may be in the performance sections. Study those. And finally, the weather questions, the metar/taf ones that do not require a figure from the supplement guide are a must! I think there are only 5 or so that don't require a figure, instead they just list the metar/taf below the question. I had two of those on my test.
The people in my class that didn't take this test seriously did not get a chance to interview, do not take this test lightly, in my opinion the test is 80% of the interview. If you want PM me sometime and i'll rack my brain for the questions that were on my particular test.
B