:eh: Bends period take away from flow velocity, but a mandrel bend is something to stay away from? You have to be kidding me. Ah, 5 years ago... sorry, I stay a bit more current. 90 degree bends are second only to 180 degree bends in their ability to rob the exhaust of heat by conduction, reducing velocity [not to mention the fact that the "formed elbows" you refer to are actually mandrel bent sections with just enough material for the bend, instead of the entire length of pipe most aftermarket headers have]. In fact, the fewer bends you can make, the higher the average velocity will be. A quick look at current superbike headers show that... yep, 2 bends total, one out of the head downward to clear the riders leg, and another up and to the back so as not to scrape the ground while giving the measured [and desired] length the engineers want to make power. For those keeping score at home, the first bend is 90, and the second is more in the neighborhood of about 80 degrees, with about 14 inches between the two. Even Ferrari's 2002 F1 engine had mandrel bent sections in it's headers, composed of 110 degree bends, and even some 45's, quite a range really. The most important thing is tuned and equal length though, not how much the bends are. and here... I just don't even know what you're saying here. The Ferrari Enzo was designed more as a technological statement than anything, and whatever isn't plugged into the system's computer was designed to make a visual statement while still being functional, and quite frankly, sharp bends catch your eye, and since a tuned length header is the most important aspect, you can get away with multiple sharp bends as long as the cross-sectional measurement stays the same.