What are the major differences between a BMW 320i sold in the UK and one sold in the US? Assuming the specs are exactly the same then the only major differences are related to the US version being left hand drive and the UK being right hand drive. Right? Well it goes beyond that. The two cars will recieve different programming or coding meaning the electronics will react differently to user inputs. For example on some US sold cars you cannot close the windows using the key fob, which is a very useful feature. The coding tailors the car to the market its being sold in, but why not have it tailored to the way you want it? There are so many things you can do with coding. Take a look at the list below which shows a mere glimpse. It's also used to enable optional features such as bluetooth music streaming without making any hardware changes.