Magnaflow is now shipping the 15821 SISO catback with both the 24" and 18" center pipe for 04-05 F-150s. And if anyone doubts the quality of the product..........DON'T! It is VERY SWEET! I have yet to install, but its FIRST CLASS IN THE BOX!
Ted

 

Fyi!
"Exhaust Systems" forum is where this thread belongs; you'll get a better response there