The sad truth is that the HP ratings are more tied in to the Marketing department than it is to the Development department. For example, the 2003 350Z has 287hp, and the the 2006 350Z has 300 hp. Yet, if you look at the track times, the 2003 is consistently (albeit marginally) quicker. Why? Well, in order for the 2006 to get to that 300 horse, Nissan ended up reducing torque by
[email protected] Also, the torque curve is more linear to redline in the 2003. BUT, when the average joe sees 300 on the sticker, instead of 287, it sells cars. And that's just one example. Sometimes I have seen cars HP ratings get adjusted for one year to the next with NO CHANGE. One recent car that comes to mind is the Tiburon, which was reduced from something like 200 to 187 or something. Those numbers may not be accurate, but you get the idea.
The point is, don't be so hung up on the numbers; there is a lot more to it than than just numbers. The 05 WRX has 227 horse. But ask anyone who has one, and they will tell you the car can be hard to drive in town, because the car has no torque until it hits boost around 3k rpm.
Of course, you have to expect that as the engineers get more familiar with the engine, they will find more power out of the engine; it's a natural progression. Just look again at the 35VQDE in the 350Z. Not only is it engineered for more power depending on application, but if you look at the engines history, it actually was introduced with an output of 255. Which, by the way was derived from the 190-22 horse VQ30DE, which was derived from the 157-160 horse VG30DE. I'm rambling...