Originally Posted by JCL

BMW doesn't make brake lines, they buy them from a supplier and form them into the precise shape. The only advantage to buying them from the dealer is that they are pre-formed, so if it is a complicated shape it may be cheaper to buy it from the dealer than pay your mechanic to make a straight line fit, using a tube bender so that it isn't kinked. It should be your mechanic's call, he can see what the most appropriate fix is.