Rotary's have a love hate relationship with boost. They love it until the engine instantly blows an apex seal which is about the equiv to a head gasket except they have 3 of them and it only takes one to make a mess. They are actually very simple engines and can produce high amounts of power but it only takes on little hiccup to ruin your day so tuning has to be very careful and monitoring your engine is vital, always good gas, keep the coolant temps low as the stock cooling system is junk and has to be replaced. I'd say normal reliability is in the 300-400 range after that it's a matter of time each person has a different experience but from what I've seen almost all of them have had a rebuild at some point. And on the down side 10MPG is in the norm. Even RX8 owners have reported only getting 18MPG on the highway stock.
2008 135i - Cobb AP, MS DP's, Berk street exhaust, AMS IC, BMS DCI, CDV delete, Quaife LSD, M3 control arms, M3 rear SF bushings, SS brake lines.