Just for review, SSDT-BI is for SSAS, SSIS and SSRS development. For database projects, they have now built that functionality back into all versions of Visual Studio 2013 (available as a separate download for Visual Studio 2012) and can be updated via Visual Studio 2013 directly. For more updates on SSDT, make sure you follow the SQL Server Data Tools Team blog.
Update: At about the same time I posted this Kasper de Jonge posted about SSDT-BI for Visual Studio 2013. Biggest disappointment is that there is NO backwards compatibility with SSIS 2012 or SSIS 2008R2 projects, so if you are only doing SSIS development on previous versions of SQL Server, don't jump on this upgrade just yet. No explanation was given for this incompatibility or if it will be fixed in a future update. Just keeps getting more and more complicated.