Today, the "feature" of GT5 DLC is most relevant to game preservationists. With the PlayStation Store for PS3 now effectively closed to new purchases (and difficult to navigate for legacy downloads), the PKG files have entered the grey market of digital archiving.
This was a standalone car DLC, a Nissan GT-R that won its class in the 2012 Nürburgring 24-hour race. Gran Turismo 5 Dlc Pkg