Dan Holmes shows how to build custom statistics:
There is a performance benefit to imported stats. The cost to compute the stats are on an “offline” table. The only downtime for the production table is the duration of the stream import.
This process does use undocumented features and it looks like it could be dangerous, but remember there is an easy undo: the update statistics statement. If something goes wrong, the statistics can always be updated using standard T-SQL.
Scheduling this code to run regularly can greatly help the optimizer produce better plans given a data set that changes over the tipping point but not enough to trigger a statistics update.
This feels like the time of thing you want to know because it’ll come in handy once, but if you feel the need to use it frequently, that may not be the best choice.