Mufflers sold online: Authenticity

[Zackelberry]

Hello, I am planning on changing the muffler of my car and considering choosing the known brands, or its just the brands that I've heard. Greddy, HKS, Nitto. upon browsing I saw many sellers and their prices ranges from 2-5k. I am wondering if its authentic. Some of them also claiming that they have JASMA registration no. I need your expert opinion on this. How can I know if the product is original or not or do you have any suggestion? TIA

[Brent]

Nitto is a tire brand. There is definitely no Nitto muffler. And the prices you mentioned are for brand new mufflers? If so, they are surely fake.