Exhaust fabrication question

[coneeng]

We have a lot of people using two 2-1 collectors with the outlets welded together to create x-pipes. You can then use bends to align the X with the rest of your exhaust system. You can see the collectors here, towards the bottom of the page: http://www.coneeng.com/collectors.html

[70 Chevelle]

Chicane, do I understand this correctly? I'm picturing 4 2 into 1 collectors. 2 off the back of the headers with the y side of the collector facing the rear, and 2 in the extension pipes before the muffler with the y side facing the front with a burns style x pipe in the ceneter connecting them. I am using 2 into 1 collectors as a visual only. In your design how critical are the entry and exit x pipe angles into and out of the extension pipe?

[Cam68SixSpeed]

Has anyone used anything from deedsengineering.com? the stuff looks nice on there site and cheap enough. Does anyone know if its good stuff?