Twin Turbo Engines as reliable as naturally aspirated engines?

[mtech8]

Really stupid question.

Are naturally aspirated cars more reliable than one that have forced induction?

I'm buying a X5 4.8i and planning on keeping it for a while (buying not leasing). I believe eventually BMW will put the new XDrive35i and XDrive50i engines into the X5. Just not sure if it will be as soon as 2009 model year or later.

The increase in power from the twin turbo engines would be great! But would that also make the car less reliable? ie: faster engine wear, more potential parts breaking down, etc?

Obviously, if the TT engines aren't making it into the 2009, the choice of the naturally aspirated 4.8i would be fine. But if it is, then it's really a hard choice of whether I should wait or not is definitely a tougher choice.

Example. If I bought the last year of the 330i vs getting the 335i. Pretty big difference.

Guess I'm just looking for justification on getting the 4.8i vs waiting for the twin turbo engines.