The E9x platform switch involved significant safety upgrades (particularly on side door collisions, frontal and offset collusions) vs the E46 chassis, and you saw that in the crash test results in Europe and the US. There's no such thing as a free lunch.
Also vs other sedan-based vehicles (Yes, the M3, whether 2 or 4 door, is a sedan, not a true sports car) ie C63 and RS4, it is quite lighter. Remember this is from 6 yrs ago, a time when carbon fiber was much much more expensive to produce.
Given all the safety upgrades and luxury items packed into M3s, think they did an amazing job with both the engine and chassis under the circumstances at the time. Moreover, vs today's competition, the M3 is still lighter. Hope the next generation will be taken one step further in terms of weight reduction.
Originally Posted by Mr.Metak2you
What is the weight comparison, S65 vs S62? I'm always amazed how much lighter the S65 is than even the I6 S54.[/
Excuse my ignorance, but I never really understood the engine weight comparison between the S54 and the S65. The S65 is 33lbs lighter (iron vs aluminum), but on the other hand the E90/92 as the whole car is 300lbs heavier than the E46...so what's the big deal that the engine is lighter?