i ordered a set for my dart shortly after they raised the prices, which they have raised again btw. if you dry fit the system together on the garage floor you will find that the tail pipes are about 24 inches apart, the gas tank is 28 in. wide, and the frame rails where you would mount the pipes to are 34 in. apart. if you put the pipes where they need to be and then mount the mufflers you can't put on the X pipe due to the mufflers being splayed at an angle / \.
i called their customer install line to find out what needs to be done and they told me that i need two people to install the system. (oh i see, two people can magically bend 2.5 in stainless tubing, where only one can't) they also pointed me to the installation gallery where there is a 69 dart with their system. the pics show a very nice professional job with almost every one of their components altered to make it fit. they even bent the X pipe to make the mufflers fit right.
if you are thinking that this system is a simple bolt on and go job you should think again.
i'm trying to decide between taking the X pipe to a shop and have it bent or cutting the X open prying it apart and welding it back up. oh, and the front half of the X doesn't land between the humps in the crossmember nor line up with hedman headers, even more work up front.
wish me luck!
