I want to know what the best exhaust system is to boost horsepower on a 2007 Mustang GT. I have read an article that exhaust systems don't really boost horsepower that much on the newer Mustang GTs. Here is an excerpt from the article:
"Mclelland explained to us that modern engines, especially those with variable cam timing like the '05 Mustang, are not going to respond to a reduction in backpressure like older engines do. This is largely in part due to the variable cam timing and wide lobe separation angles used on modern cams. As a result the exhaust system plays very little role, if any, on scavenging and drawing the intake charge to the cylinder. It is no surprise then that we saw no significant power gains on the dyno. The factory '05 mufflers apparently flow well enough to support as much as 425 horsepower. Once you add a blower or increase displacement is when you'll see some gains from the less restrictive Flowmasters."
Source: http://www.fordmuscle.com/archives/2005/03/05Mufflers/
"Mclelland explained to us that modern engines, especially those with variable cam timing like the '05 Mustang, are not going to respond to a reduction in backpressure like older engines do. This is largely in part due to the variable cam timing and wide lobe separation angles used on modern cams. As a result the exhaust system plays very little role, if any, on scavenging and drawing the intake charge to the cylinder. It is no surprise then that we saw no significant power gains on the dyno. The factory '05 mufflers apparently flow well enough to support as much as 425 horsepower. Once you add a blower or increase displacement is when you'll see some gains from the less restrictive Flowmasters."
Source: http://www.fordmuscle.com/archives/2005/03/05Mufflers/