I've heard of ignition coils going, air con leaking or packing in, gearboxes going, there was a few more small things but I can't remember. The only bad thing I've heard about the astra is the turbo going but you can replace it with the stronger VXR one which would solve that problem. I'll have a look in that section and see wha it says, just really wanting to know from people that own one what they think.