What color is the smoke?
Black - you're running rich, and can probably fix it easily.
White - you've broken/blown something, and prepare to spend some bucks! ie. ring, piston, head gasket, turbo.
Turbo seals going out, or play in the shaft can cause this too. It will cause white smoke, per the oil dumping straight into the turbo airflow path and burning.
Pull the MAF pipe and check the shaft play, front to back and side-to-side. Grab the shaft nut with some pliers, and check it with firm movement. (I had one fool me by just checking w/ my fingers). Pull the downpipe loose, and check the exhaust side of the shaft too.
And "yes" do a compression check on all cylinders. It's easy, and very useful info!
