Any word on why reviews have rated the horsepower and torque higher and lower than the 300/300 reported by BMW? Some reviews I've seen have rated horsepower a little above 270 while some rate it even above 300. And as for 0-60 times, I've seen anything from 4.8 (even with an auto) to 5.5 which is reported by BMW. Are the twin-turbos that inconsistent or are some of these people just overly hopeful?

HP ratings are a tricky thing. There are two main ways of measuring horsepower: at the crank and at the wheels. Most companies report hp at the crank, while some magazines report at the wheels. Since some power is lost in the transmission and differentials, wheel hp is generally less.

Many reviewers believe that BMW underrated the 335i's power in order to protect M3, and Z4M sales. So that would explain the higher ratings. The 335i actually beat the Z4 M-Coupe in a C&D track test.

BMW (along with many other German automakers) are known for underrating their car's 0-60 performance times. They take the "under-promise, over-produce" mentality.

The turbos arn't inconsistant, people are.