black smoke = poor mixture (too much fuel to air - running rich).
loss of power below 3k RPM is often attributed to EGR, however I would suggest you're likely to have a hole in one of your charge pipes.
There are only 2, one goes from the cold side of the turbo and runs across the front of the gearbox into the wing where it connects to the intercooler. the other goes from the intercooler in the top of the wing across to the inlet manifold.
The bottom ones are prone to splits on the bolt in the bell housing of the g/box, but they should easily split / pop anywhere.
if you're really unlucky you've got something like a stone gone through the intercooler and popped that.
1999 156 1.8TS Sport Pack 3
2001 166 3.0 V6 24V Super
2003 156 GTA 3.2 V6 24V
2005 156 1.9 JTDM-Jet Sport
2008 159 1.9 JTDM Lusso
1997 GTV 2.0TS Lusso
2001 147 1.6TS Lusso