I am getting a little annoyed at saying this on a lot of posts involving X-pipes and what REALLY happens in an X-pipe....here goes. Firing order is one integral part of the X-pipe advantage, but there is another reason to get an X-pipe even if your firing order is even like our V6s. When one exhaust stroke heads down the pipes, and meets the cross-over, the exhaust will spread to both ends of the exhaust, this then creates a very slight vacuum on the other side of the exhaust piping. This slight vacuum frees up resistance from the next exhaust stroke, which is on the other side of the motor (obviously), which makes a good flowing exhaust that little bit better. This pattern continues after the first exhaust stroke all the way until the driver turns off the motor. A great advantage about this is that since our 6s have an even firing order, this vacuum works to almost 100% efficiency, with the V8s and odd firing order, the efficiency is reduced to around 85-90%. So, a V6s even firing exhaust will ALWAYS flow better with an X-pipe if the same exhaust setup is used.