I am wondering if anyone had actually documented performance gains from exhaust mods? I realize that a lot of people think their car "seems" faster when they add Bassani or Flowmaster parts.

However, personally, I only want to do exhaust mods if it will actually increase performance. Any proof of that? Thanks.

 

Magnaflow AxleBack Mufflers = 0 HP gain. Only change sound and appearance.

 

Here is a link to a thread on another board. This guy did a baseline dyno pull, completely stock. Then installed Magna-flow X pipe with cats and MagnaPack mufflers and did another pull. He says it gained as much as 10hp and 15ft.lb tq in some places. He also posted his dyno sheet.

Link on another board.

 

I went from 255rwhp/271rwtq (yes, pretty low for a 5 speed gt*shrug*) to 268rwhp/288rwtq with the magnaflow catted x + catback, and it still feels like there might be an exhaust leak too.

This is without a tune also. And the a/f seems to be completely safe.