My downpipe developed a crack and split at the flange that connects it to the exhaust housing of the turbo. There's roughly a 5mm gap going 180-degrees around the flanged discharge piping.
.. I drove the car and it doesn't move at part-throttle. Getting this fixed soon, but in the meantime .. would you run this car in this condition if you had to? .. Would this cause it to run lean?

 

no it wouldnt cause it to run lean but your wideband will read lean if there is an exhaust leak before it in the exhaust

 

If anythingg it would cause it to run rich since the 02 sensor isn't seeing as much exhaust. A friend of mine is experiencing the same problem right now but its worse than yours his is about half inch gap due to the fact he brokke a bolt off in the turbine housing and the dp flange is warped.