I planning to buy this muffler
https://parts.levittownfordparts.com/oem-parts/ford-muffler-and-pipe-be8z5230c to dissipate the loud sounds from the engine to sounds better. I just like to know if anyone has experience with the actual product of is okay if I install an aftermarket free-flowing muffler?[/QUOTE
There are many choices available. The cat back system that the ST Version has will fit the basic Fiesta hatchback and it sounds good.
Several of us here have seen some video clips of lower priced mufflers like Rumble or Thrush that a muffler shop did by just adapting and welding them on in place of the original ford muffler. The one that didn't also have the resonator deleted sounded nice.
Given the built in limitations that Ford has imposed on the basic Fiesta, those simple and inexpensive muffler installs give a nice return on the money spent.