Those numbers are to the wheels (not measured at the crank, like the manufacturer does), so you have to compensate for losses in the drivetrain. I've heard that front wheel drive cars usually lose 17% in the tranny. So the way I figure it, 141hp is roughly 170 to the crank, which is still 5hp short . . .
It could be due to it being a new engine, it could be that Nissan is still exaggerating hp numbers, it could be that the numbers weren't corrected for the atmospheric conditions. The debate on the SE-R list is whether the helical limited slips saps more hp than an open diff.
John
2.5S 5sp