I'm running a Neu 1527 1.5y (825kv) in a 19lb. 4wd offroad buggy on 8s geared for 50mph. I get max temps in the range of 160-165F (on 90F summer days). As far as I'm concerned, its the perfect motor for mine:
http://www.rc-monster.com/forum/showthread.php?t=26979