Looking to purchase 3-series, E9x or 2012+? 6 cylinder or 4 cylinder turbo?

[BMWAL99]

I am looking at purchasing a BMW 3-series. I am leaning towards the E9x due to the 6 cylinder being proven. Which one is more reliable? The 328i 4 cylinder turbo or the 6 cylinder? What about the rest of the car?

[Das Omen]

I've driven the turbo 4 and although it couldn't touch my 335I it was still mildly entertaining. It has some pretty nice low end torque but as you mash your foot down and get higher rpms, it starts to feel a little rough and the engine sounds like its trying a little too hard. Where as the 6 would be smooth in the same situation. Benefit of the 4 is of course better mileage (if that's a key factor for you). But if you occasionally like to do some stop-light racing, you'll probably be underwhelmed by the feel (and will lose at least half the time).
If you're just an all time "casual" driver, definitely go 4cylinder.

[Mima]

Depends what 3-series you are looking at. 6 cylinder turbo or naturally aspired? Don't know what your budget is going to be for the car but any turbo car implies more maintenance. If "turbo" is the word, then "more" is the answer.

[BMWAL99]

I meant the 6 cylinder naturally aspirated motor. My number 1 concern is reliability. I can do most maintenance myself with the exception of a motor rebuild / trans work.

Also is the manual or auto preferred for reliability?

[floydr]

I meant the 6 cylinder naturally aspirated motor. My number 1 concern is reliability. I can do most maintenance myself with the exception of a motor rebuild / trans work.

Also is the manual or auto preferred for reliability?

The F3x N20/N26 has been mostly reliable - there was an early problem with the vacuum pump but nothing I've seen since. Most people don't tune it (more people do so with the N55), which contributes to reliability. It's probably about as reliable as the N52, assuming no tuning; hard to say. As noted, it's got a bit more oomph, but isn't as smooth.

The ZF E9x 6 speed auto, and the F3x 8 speed auto seem quite reliable. The 8 speed is a major contributor to the better mileage of the F3x compared to the E9x.

For either car, you will need an OBD II scanner that reads BMW-specific codes: BavarianTechnic, Torque, Carley, etc.