Speaking to Eurogamer, publisher said:
The development team felt they needed a little bit of extra time to optimize the game
This might be Namco’s response to UK retail troubles after Capcom delayed Asura’s Wrath on a similar note. Whatever the reason may be, we hope the game when released, will be well worth the time it received with this delay.
Ridge Racer: Unbounded is being developer by Bugbear for PC, PS3 and Xbox 360.