I would personally be hesitant to buy any ~2 year old car with >50,000 miles. But if the car comes from a reliable source and has complete maintenance and service records I don't see it being a huge issue. As a general rule these cars are finicky and cost more to maintain properly than other makes/models. My personal advice would be to look for a car that still has some warranty (factory or CPO) available and lower miles, even if it's a year or 2 older.
2008 E90 335i // Black Everything // photos
COBB tuned / QTP e-cutouts / Helix FMIC / cp-e DCI / AWE BOVs / Black M6 wheels + Toyo Proxes
(and yes, I am a girl)