I lost this point. But how we can be sure if the mule car tested by C/D was able to perform as the same at sea level? Ok, turbocharged engines are "less" affected by the altitude, but this not concretely prove that the car perform as the same as the sea level or should be fast as the same as the press car tested by Auto, a car dyno'ed at 489 PS. We can only GUESS this although it may be slightly different. GUESSING, then compare that with the Auto GT-R's power, it's not a proof for we all. The only thing we can say is that the 2013 GT-R press car ran the 60-124 mph as fast as the uncorrected time of the 2008 test mule. We know the older test was made in 52 deg F, humidity 33%, 25.75 inHg (this does not explain yet why C/D applied so strong correction for just a slight temperature and humidity difference). C/D looks like usually use older correction standard, so referred a 60 deg F day with 0% humidity and a barometric pressure of 29.92 in-Hg looking their site. "To eliminate the effects of weather on performance, we employ proprietary empirical correction factors to adjust all results to dry air at 14.7 psi and 60 degrees Fahrenheit using PsyCalc 98 software to crunch the weather data" With this weather condition difference, considering also that turbocharged engines are less affected by barometric pressure, far away different than guessing a power figure, we are not able to explain 72 hp between both cars. Also, I believe the 2013 car has all HP claimed. This does not means a 545 hp mule car tested 4 years ago, but also not explain a 473 hp engine could be able to perform at 4200' so close to the 2013 car referred. Concerning C/D test compared with 2011 GT-R 530 PS supertest by Sport Auto, weather conditions are close, just slightly different by "6 deg C". 11 vs 17 degrees C. Their 50-124 mph times (80-200 km/h) are exactly the same. 9 seconds! According with accurate Maha's dyno charts, the improved combustion cause of cooler air, an engine from the correction standard gain around 1% of power every 5 degrees C. If you like to guess. Draw your conclusion again about GT-R test mule power. <A BORDER="0" HREF="http://www.supercars.net/PitLane?displayFAQ=y"><IMG BORDER="0" SRC="pitlane/emoticons/wink.gif"></A> According with your source: "Another Pearl Blue, this time delivered in the US. Within a week of arriving, this customer's car put down 474whp and recorded 0-60 in 2.8s, 1/4 mile in 11.07 @ 124.45 mph." http://www.dragtimes.com/blog/2012-nissan-gt-r-on-the-dyno-and-at-the-drag-strip "We dyno tested the 2012 Nissan GT-R on a Mustang AWD dyno at HP Logic in West Palm Beach, FL where it put down 474 horsepower and 420 ft-lbs of torque to all 4 wheels. HP Logic has dyno tested many 2009-2011 GT-R that average around 430 horsepower on the same dyno. The 44 horsepower increase we saw on the dyno from the 2012 over the 2009-2011 cars matches up perfectly the 45 horsepower increase stated by Nissan. If we use a 13% driveline loss from the GT-Rs dual clutch transmission and AWD system, we come up with 545 horsepower and 483 ft-lbs of torque" Drivelines losses still are quantities. GTR's dual clutch transmission and AWD system seems to cut 71 hp on dyno. This means that 2009-2011 GT-R that average around 430 horsepower on the same dyno are estimated around 501 hp at crank. "Even though the 2012 Nissan GT-R is a portly 3800+ pounds, it's new found power combined with a super fast shifting dual clutch transmission, all wheel drive and launch control systems allowed us to run a 11.07 @ 124.45 MPH at Palm Beach International Raceway in West Palm Beach, FL, which appears to be the best time recorded for the new GT-R so far. Average times for stock 2009-2011 GT-R's in our database are around 11.7 @ 120 MPH, so the new GT-R is clearly much quicker and faster." This also means if that average times for stock 2009-2011 GT-Rs in our database are around 11.7 @ 120 MPH on drag strips, the C/D test mule tested 11.5 @ 124 MPH seems much closer to the 2012 Nissan GT-R. This last car did 60-124.4 mph 8.27 secs.