Be aware that the Sort component is a blocking component in SSIS and that it can drastically affect performance if you transfer a lot of rows. If this becomes an issue, you can try to clean the duplicates in the sources themselves or to drop the data in a staging table and do the clean-up there.
On a side-note: if you are using the built-in Slowly Changing Dimension component, this one has performance issues as well, as a OLE DB command is issued for every row. If you have a lot of updates, performance will go down. Since you posted this question in a 2008 forum, I assume you're working with SSIS 2008. Performance wise I would recommand the MERGE (T-SQL) operator.