My son in law's Vectra had a spring break and had to have a new tyre fitted due to the damage the spring caused. As an ex Vauxhall apprentice and a Vauxhall owner myself I was particularly interested in the cause of the problem, especially as no one else has the answer including Vauxhall. Last night I spoke to a spring manufacturer, he was very familier with this problem and reeled off all the makes and models with the same fault. He said that they are quite happy to make a spring for a customer to his drawing but sometimes the spring fails and they say 'you made it wrong' to which he would tell them how to improve the design to prevent failure. A compression spring should be parallel but the one Vauxhall fit has the last couple of turns reduced in diameter which causes a high stress point in the spring and causes it to break. The reduction in diameter is to do away with an extra component that mates with the spring and the suspension. So the buck stops with Adam Opel who designed it in Germany. I imgine a product recall now would probably bankrupt the place. So when buying the next car avoid the one with the reduced diameter coil springs.