Honestly, I'd leave them both on unless you have a bloody good reason to turn them off and you have code that creates stats on every temp table that you create and use or unless your temp tables only every have less than about 100 rows in them.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability