Yes, you can change the exhaust of a Yamaha R15 M. Several aftermarket options are available, including high-performance exhaust systems from brands like Akrapovic, SC Project, and Yoshimura. These modifications can enhance the bike's sound and potentially improve performance. For example, installing a full system Akrapovic exhaust can cost around 5,000 INR and is known for its loud and distinctive sound. Additionally, standard aftermarket exhausts that fit the R15 V3 can also be used on the R15 M, offering a more affordable alternative.