Originally Posted by msheredy
Here is a screen shot from superstreet online. These alphawerks headers produce 14 HP and 15 ft lbs. There must have been something else going on with that particular car.
not the same company, I believe it was these guys, maybe they just weren't experienced at header tuning, seems they don't carry many parts for the IS300 anymore.
http://www.skunk2.com/exhaust/index.php