First, have someone start the car while you stand behind it. That'll tell you if the turbo seals might be leaking or the valve guides are going. Next, follow the car while someone else drives it and watch for the telltale smoking or puffs. If the tail pipe smokes fairly steadily when the car accelerates, then suspect the rings , if the smoke intensifies as the car picks up speed suspect the turbo seals, if it puffs periodically when the car is shifted then the valve guides are going.
Then have a wet/dry compression check done to isolate the cause. If the engine has been properly looked after it should not smoke, these engines are strong with good oil control rings. The valve guides on the older engines are a bit loose which keeps them lubricated but can lead to puffs of smoke, especially if thin oil is being used.
One exception is if the engine has been idling for a long time, say 20 minutes, it can smoke something awful for a few minutes as these engines tend to pile oil up into the clylinder head at idle and then suck it down the valve guides as soon as you begin driving. Another quirk is the older 2.0 engines tend to smoke a little if the oil is too light, say 5W 30 or even 10w30 in summer. Heavier oil or 5W 50 synthetic will generally stop this smoking.
