Both the N54 and N55 engines are known for oil consumption that can range from acceptable to concerning. Understanding the causes and current state of your engine is important before tuning, as increased boost and combustion pressures can worsen existing issues.
Common causes include: valve stem seal wear (causes blue smoke on startup after sitting), PCV valve failure (causes excessive crankcase pressure), turbo seal wear (oil in the intercooler piping), and piston ring wear (high mileage). The N54 is also susceptible to OFHG (oil filter housing gasket) failure, which causes oil to mix with coolant.
Before tuning: check oil consumption rate over 1000 km, inspect for visible oil leaks, check intercooler piping for oil residue, and monitor crankcase pressure if possible. Address any leaks before tuning — increased boost pressure will worsen them.