i have a 4-1 dc ceramic header on my gsr and its dented at the bottom kinda bad and it has a small crack where all 4 pipes come together how much would this affect the performance on my car? btw the other mods i have are intake if that helps... thanks

 

It will be dependent on how badly it is dented....have the cracks welded or if you dont have access to a welder at least try jb welding them. That should help some.