[GoingTooFast]

Trend definition:

1. The general direction in which something tends to move.
2. A general tendency or inclination.
3. Current style; vogue: the latest trend in fashion.

intr.v. trend·ed, trend·ing, trends
1. To extend, incline, or veer in a specified direction.
2. To show a general tendency.


Thesis:

Inline-6 engine is a marketing thing for BMW.


Evidences:

It represents a significant weight penalty regarding 4 cyl. engines which is obviously detrimental for the "Sheer Driving Pleasure" and "Efficient Dynamics".

1. Less fuel-efficient
2. More emissions
3. More weight over the front axle
4. Higher COG
5. Lower aerodynamic efficiency
6. Less favorable power-to-weight ratio.
7. Tendency for higher power output which equates to an even higher overall weight
8. Weight being the worst enemy of a car's dynamics: braking, accelerating, cornering


Commercial advantages:

6 cyl. tradition and image; development cost (the turbocharged engine is on the market since 2006, it's basically the same engine or using already proven and even older technologies such as Valvetronic); a 4 and 3 cyl. engine derivatives can be easily obtained by simply cutting out 2 or 3 cylinders with most of the other engine components being shared; the 6 cyl. engine is regarded as a luxury item associated to premium, heavier, pricier cars whereas its 4 cyl. counterpart is not despite the fact of sharing the very same technologies and most of the components.


Conclusion:

A 6 cyl. engine is a marketing thing for BMW with important disadvantages to as far as a sportier driving experience, fuel-efficiency and emissions go.