Which brings me to my point which bears repeating - How easy it is to steal a bimmer depends on whether it's brand new or recond. Brand new bimmers (previously) come with four keys and now the F10 comes with two keys, which are all given to the new owner. A recond bimmer may come with the complete set of keys (if you are lucky), but it's usually less. So there is a high possibility one or more of your keys are in the hands of the recond car dealer or some other unscrupulous people.
My personal advice - BUY THE BEST STEERING LOCK YOU CAN AFFORD - if you buy a recond F10, or any other recond bimmer, and get less than four or two keys. In fact, even if you have a brand new bimmer - BUY THE BEST STEERING LOCK YOU CAN AFFORD. After all what's a few hundred ringgit to safeguard your quarter-of-a-million-ringgit, or more, investment.
Salut