go listen to a Datsun with triple webers.. you might change your mind..

 

You can also run the snot out of an inline 6!

 

I've always disliked the E46 M3 I6 (tinny and harsh) but the same engine in my Z4M has a deeper, throatier sound that is much sexier. The old Datsuns sound awesome! I'm not a huge fan of the 2JZ, personally.

Honestly, I do prefer the sound of most V6s over an I6. The sound of an NSX at full bellow is far better than any OEM I6 I've ever heard. However, owning an I6 just lets you appreciate how smooth they really are compared to most V6s. My Z4M revs to 8000 rpm and it does so just as smoothly (if not more so) than the S2000 (which, to me, has always been the epitome of high-rev smoothness).

 

I actually found the article rather superficial and lame. My wife's Jeep has an I6. Let's be honest, the BMW I6s are smooth because BMW sweats the details and uses good engine mounts. It's not because the motor is so much smoother. The Jeep isn't rough but I've felt I4s that are smoother at idle. A good friend bought a BMW 530 years back. When it was new the idle was very smooth... couldn't feel it sitting in the car. When it got up their in age things changed. It wasn't glass smooth and certainly a new Honda Accord V6 was smoother. So either he lost a cylinder or something that wasn't inherent to the motor's layout changed.

Basically, yes the I6 is inherently balanced but as a mechanical system a 90* V6 with balance shaft and split pins (GM 3800, Mercedes) is also inherently smooth (note I've included the balance shafts as part of the system). Even an I4 can be inherently smooth with balance shafts. The I6 comes with inherent disadvantages too. The obvious one is packaging. Less obvious is weight, block stiffness and crankshaft stiffness. I6s have long cranks. To prevent windup along the length of the crank it needs to be heavier than a V6 crank. It also has more fluid bearings (typically a journal between every cylinder vs every pair. That results in a loss of efficiency. The weight is just that, weight. Because the engine is so long it's harder to get that weight back in the chassis where you might want it.

All things in engineering are compromises. BMW makes real compromises to put I6s in their cars. I firmly believe they have stuck with the design in large part because it's now a marketing claim rather than any sort of true engineering advantage.