In carby Cultus there are 3 mufflers in total. If any of them will go bad you will either hear a rattling noise or the exhaust note will change it will become sort of heavy.
Wheels bearings available at Suzuki dealership's are different than the one's available in market their part number's are different and they are specifically designed to be used as wheel bearings.
While most of the bearings available in market are general purpose. NTN and Nachi are the companies to look for if you are buying bearings from market.