Exhaust manifold/headers
 

I added a tomei exhaust manifold to my car but its not as loud as I had originally expected even tho cat and cat back is all stock if leak in exhaust gasket how can you tell

Punctuation.

If there is a leak it will be louder than if there was no leak...

This. Exhaust leak usually means that it will sound like you are piloting a B52. At least that is what my '89 Volvo 240DL sounded like when the exhaust fell off on the highway one day.

I thought so just wanted to make sure I guess a cat back can make it louder