Well, the "Auto. Create Stats" and also "Auto. Update Stats" could be a real pain;
I recommend to disable it.

THe sufficiently maintain the required statistics you could implement a SQL Agent Job
(or TSQL task for the MP) doing this:

use [MyNAVdb]
go
exec sp_updatestats
go

exec sp_createstats 'indexonly'

To get rid of the already existing auto-stats, you could exec this script
(part of the NAV/SQL Performance Toolbox)

declare @id int, @name varchar(128), @statement nvarchar(1000)
declare stat_cur cursor fast_forward for select [id], [name] from sysindexes where ((indexproperty(id, name, N'IsStatistics') = 1) or (indexproperty(id, name, N'IsAutoStatistics') = 1)) and (isnull(objectproperty([id], N'IsUserTable'),0) = 1)
open stat_cur
fetch next from stat_cur into @id, @name
  while @@fetch_status = 0 begin        
    set @statement = 'DROP STATISTICS [' + object_name(@id) + '].[' + @name + ']'   
    begin transaction
      --print @statement
      exec sp_executesql @statement
    commit transaction
    fetch next from stat_cur into @id, @name
  end
close stat_cur
deallocate stat_cur

(Afterwards you have to run the sp_updatestats/sp_createstats thing)

This would update the existing stats and create missing index statistics. Rgarding the "tuning engine": I do not recommend to use it, as the recommendations are oftenly somewhat "starnge" and actually sub-optimal. I recommend to monitor the system frequently with the SQL Profiler to learn about "bad queries" and fix those individually ...

exec sp_updatestats
go

Create Stats
exec sp_createstats 'indexonly'
go

CLEAN AUTO STATS
How to clean Auto Stats
(KILL ALL STATISTICS)

Display Stats:

select [id], object_name([id]) as [tabname], [name], isnull(indexproperty(id, name, N'IsStatistics'),0) as [stats], isnull(indexproperty(id, name, N'IsAutoStatistics'),0) as [auto]
from sysindexes
where ((indexproperty(id, name, N'IsStatistics') = 1) or (indexproperty(id, name, N'IsAutoStatistics') = 1)) and (isnull(objectproperty([id], N'IsUserTable'),0) = 1)

Delete Stats:
declare @id int, @name varchar(128), @statement nvarchar(1000)
declare stat_cur cursor fast_forward for select [id], [name] from sysindexes where ((indexproperty(id, name, N'IsStatistics') = 1) or (indexproperty(id, name, N'IsAutoStatistics') = 1)) and (isnull(objectproperty([id], N'IsUserTable'),0) = 1)
open stat_cur
fetch next from stat_cur into @id, @name
  while @@fetch_status = 0 begin        
    set @statement = 'DROP STATISTICS [' + object_name(@id) + '].[' + @name + ']'   
    begin transaction
      --print @statement
      exec sp_executesql @statement
    commit transaction
    fetch next from stat_cur into @id, @name
  end
close stat_cur
deallocate stat_cur

AFTER > Scheduled Job
sp_updatestats and sp_createstats 'indexonly' (as posted previously)

fonte Mibuso