Back fire after engine turn off

[kookku]

Kizashi SE 5000mi, problem with back fire after turn off ignition, first notice when it was 3000mi and progressively presented,
took to dealer had oil changed and technician found nothing wrong but a pop ( back fire after engine shut off still there).

Also, since bought this car a booming sound from exhaust louder than any other Kizashi dealer never find out and told me normal
but other SLS, GTS were much more pleasant than SE.

It seems to me that Suzuki technician less capable to service there product than other brands

[chevydually]

the problem may be baffle in muffler have had a couple in grand vitra muffler