Originally Posted by 2010 4 DW
If you race your car then 1 7/8" will get you in the low 10's if not the 9's so make sure to buy what you can afford at the end of the day.
Here is Padre SS running 10.3's with JBA 1 7/8" LT's and FULL exhaust so the 409ss should not a deal breaker. SLP products are 409ss and I see none of their parts failing on this forum.
1 7/8" is definitely sufficient for the vast majority of Camaros running around out there.
No one is suggesting 400 series stainless steel is so poor that it will quickly fall apart or fail. It is OEM grade so it will have a decent service life. It will surface rust pretty quickly though and it may have to be replaced at some point while you own the car. Neither of those will ever happen with 300 series. It is a give and take like anything else.