what exhaust actually improves performance?

[FACEman650]

Hi guys, I guess this question has been asked but I gotta ask it anyway. What exhaust system actually does improve your bikes performance?

Please post links and graphs. I'm doing a bit of research on the subject.

 

[Pote]

 

[user 5710]

 

[volroom]

 

[Freez]

 

[Losper]

 

[volroom]

 

[Rooikat]

 

[chicco]

 

[Dux]

 

[TVB]

 

[Rooikat]

 

[SuperDavexlv750r]

 

[Freez]

 

[volroom]

 

[TVB]

 

[alanB]

 

[Freez]