A tuned BMW doesn't require dramatically different maintenance, but it does benefit from increased attention to certain areas. The additional performance comes with marginally higher thermal and mechanical loads, and proactive maintenance ensures long-term reliability.
Oil: consider shortening your oil change interval by 20-30% from the factory recommendation. Use high-quality oil meeting BMW LL-01 specification (or LL-04 for diesel). Synthetic oil handles the additional thermal load better than semi-synthetic.
Coolant: monitor coolant level and condition. The cooling system works harder with increased power output. Consider a coolant flush at regular intervals.
Spark plugs (petrol): tuned engines are more sensitive to spark plug condition. Replace at or before the recommended interval with OE-specification plugs. Some owners running higher boost benefit from one step colder heat range.
Fuel: consistently use the recommended fuel grade. Never run a tuned engine on lower-octane fuel than specified.