The E90 Bmw 330i is half a sec quicker to 60 than the lighter 130i, 320i is just faster than the smaller 120i, 325i is a significant 7 mphs faster than a 125i and even the new 320d manages to trash the 120d,not only in acceleration but also in top end!
Why the abt 130 lb heavier e90 can so consistently out-sprint the 1er?
My fav conspiracy theory: they put the more powerful motors to 3er and the rest to einsers.
Reason:the big sister must be faster than the little sister..