Deinately check compression b/c you don't want to buy a damn Rotary that is going to die on you in a month due to apex seals. Lord knowns unless you know and enjoy dealing with those piece of shit 2 piece apex seals on your own and rebuilding a rotary, you'll be paying out the ass for a rebuild or new engine. Also when you take it out on a test drive push it b/c sometimes assholes put Catco cats. on them after the stock ones go bad and sometimes you end up melting the cats. and then thats a bitch to drive until you can get a new exhaust done or buy the Racing Beat shit. Do the FCs have Oil Metering pumps? I'm not too familiar with the 13B I do most of my engine work on 12As, but if so also check that leaks end up being a pain in the ass and i know when I tried changing a couple the little screws like to break. Good Luck!
Rotor On!!!
Tony