Radiator and thermastat went at about 227000km.
Muffler and cat went at 25000km.
Many belts and hoses has needed replaced over the time I've owned it.
New battery, alternator, and work on the transmission oil pan were needed around 240000km.
Great car, takes a beating, but you need to know a bit about cars to keep them maintained. Mine's top speed was 175km/h while at about 235000km. The 3.1L has great power and never fails. Its only bad on gas if your very heavy on the petal. Great car, mechanically the same as a cavalier.
Good review. A bit of a note though - it's the same as the Celebrity and its other A-body cousins (Century, Ciera), not the Cavalier. The Cavalier's Pontiac counterpart was the Sunbird/Sunfire.