The basics: all fluids either flushed or exchanged, including trans, ptu, rdu, coolant and brake.
Also check turbo piping for loose clamps, cracked piping in the clamp area, and pooling oil in the pipes. A light misting is normal.
Take pipe which goes from intercooler to throttle body, and disconnect at the intercooler. Check crud buildup with the engine oil dipstick. Less than say a 1/4 " is ok. There is a HOWTO on checking and cleaning the intercooler.
Secure the turbo piping at the wastegate solenoid atop the intake manifold. These are the small diameter pipes coming off the solenoid.
All I got ... For now