Got the Japanese version of GT 5 Prologue and are feeling left out at all the new goodness coming on the Western versions of the game? Well, don't - the Japanese version is getting an update to 'Spec II', this Friday at around Noon. To update, select News from the My Page, and then press the PS button.
Note that after updating, you'll lose your replays and the event data will be cleared although you'll keep all your credits and cars and any cleared events up to A class, so you won't need to do those again.
Update
The full content included in the update isn't known yet - it may or may not contain things like 2 player mode, cars, tracks etc.
Update 2: Spec II might just be the same patch PAL owners are getting just now - ABS removal etc. Probably not any new tracks or cars...