can't tell you much about cheaper ones. these are the fake ones i bought and they were a perfect fit:
Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com
size IN 51 OUT SIZE A. it's also seller other people bought from as well for their cars.
if cost isn't an issue, i would always go for borla. my logic is that if you get anything else, you will always have the creeping doubt in back of your mind if you should have gone louder. possibly making you regret your purchase.
but the opposite is true. if you go borla and decide you don't like the sound or its loud, then you have peace of mind knowing you tried the loudest and it wasn't for you.
if i were you, i would check your facebook group for your area. see if someone actually has borla or MBRP or other exhaust installed and if they will let you listen in person.