Um apparently Holden here in Aus is using DI or as they promote it
SIDI (Spark Ignition Direct Injection) link following.

http://www.themotorreport.com.au/41843/2010-holden-ve-commodore-sidi-first-drive-review
They advertised the hell out it when it was released here.

And yes it does use much higher pressure etc.
I know its a piston engine

Regards David (Aus, Vic)