http://www.automobilemag.com/reviews...est/index.html
Automobile mag finally did some tests and comparison between the n54 and n55.
"And now to the N55: well, it doesn't, in fact, make as much power as the others N54s we've tested, but it does make slightly more torque. Peak numbers were 266 hp and 302 lb-ft. Before you start typing your "N55 sucks!" forum posts, let's remember that while the N55 put down 10 less horses than two of the N54s, a third N54 produced 10 more horsepower than the others. Meaning: 10 hp is within the noise when you're at this power level -- it's a variation of less than 4%. And you can easily see 4% variance between runs on the same engine."
"The end result? We can finally and directly compare an early N54, late N54, high-output N54, and an N55. The N55 exhibits less turbo lag in normal street driving, and even though its peak output was near the bottom of the group of engines we've tested, it's still well within its rated peak horsepower output -- and well above its rated peak torque output. Let the N54 vs N55 war continue!"
I guess some people's butt dynos aren't as great as they say.