I just talked to the Nissan dealer here and they said they are expecting the 08's in Sept and they supposed to be 315-318hp from what they were told

 

dealer = lie

 

When you consider the changes to the engine in the 2007 Z, I highly doubt that an auto-maker would decide on another engine change to the Z in the next model year.

Auto-makers make the most money when they are able to implement the least amount of costly engineering changes to a platform. In general, the longer a platform exists/sells, the more profitable the platform is.

Most engineering changes are to reduce warranty costs, increase craftsmanship, avoid recalls, improve JD Power results, improve their throughput, reduce the cost of parts from suppliers, or spice up (e.g., new fascia or more hp) an old platform to compete with their competitors.

Therefore, I think it's safe to say that the 2008 will essentially be unchanged from 2007.

Then again.....I could be wrong. lol