Seeing double

At first glance an identical pair. My car is having its 3 year service and I have a loan car today. Actually they are quite different. The loan car on the left is a BMW X1 1.8i S drive. Anne's car on the right is a BMW X1 2.5iM X drive. From the back the only difference is single pipe vs twin pipes. M symbol on the 2.5 and bigger wheels but lower profile types on the 2.5. Also the 1.8 is an 1800cc 3 cylinder non-turbo engine with very basic accessories whereas the 2.5 is a 2000cc turbocharged engine with many extras.