Exhaust and Air Locker

Does ANYONE make a cat back exhaust system for a 2004 Chevy Express 6.0ltr???
 
And can anyone recommend an air locker for the same van?

I am sure the local 'roll your own' exhaust maker can make a stainless system for less than the local OEM replacement.  I have done this (successfully) on a V6 Contour!