Reading supplements will hurt, not help you. Why? Supplements are exactly that: supplements to the primary readings of a course. Your professor may not cover some topics, or may use different vocabulary to reference the concepts, or may take a totally different approach than the supplement. It's much harder to unlearn something than to learn it for the first time, so these differences could hurt you. I've only read around 20% of any supplement I own, because I selectively read them for topics we've covered where the supp agrees with my professors' approaches.
You should stay clear of even the CivPro E&E (the gold standard of supplements) because even the latest edition is out of date with respect to certain topics. The only possible exception I could think of would be to read a little about present and future interests in property to get some familiarity, since that is a very static area of law and is pretty confusing at first, but its not necessary and your time will be much, much better spent chilling out, drinking, and having BBQs.
Hear us now and believe us later: you can't brute force law school, so just chillax. Seriously.
I'm going to disagree with some of this. I found the E&E's to be helpful for introducing tough topics and laying some groundwork. Should you take notes on the E&E? Make an outline of it? Of course not. But giving them a once through before law school is just going to give you some background on the subjects. When you arrive at them later, you'll have some familiarity with what is going on.
Adjust according to your professor.
Maybe you guys have godly reading comprehension or memory or something, but after reading 6 E&Es + other stuff over the course of a few months, I could barely remember what the big topics were for each course. But when I saw it in a case, most of it came back to me. And when I reread the E&E, it became even clearer.
It was also helpful for outlining earlier in the semester because I could take a look at the syllabus and get a sense of what topics we were going to cover and with what detail. Always good to have the "big picture" stuff in mind.
While I also agree that you can't entirely brute force law school, you can seriously give yourself a leg up by studying the shit out of your classes, learning how to write an exam, and getting in your professor's head. I haven't discovered how much studying is actually necessary to get good grades. I know overstudied the hell out of first semester, but I also did very well. I'd rather do that than the opposite and take a gamble.