Needing more performance, MPG's and sound from your 2015 - 2017 Expedition/Navigator? Look no further! All of SPD's catted downpipes use the highest grade catalytic converters and larger 3" diameter mandrel bent tubing which improves throttle response, mileage and overall performance while reducing turbo lag and exhaust temperatures. 
 
On all SPD Performance's Aluminized Steel Catted Downpipes, you get:
Increase in performance
Improved turbo spool time
Better fuel mileage
High flow catalytic converters 
High temp silica ceramic coated for long life span
Factory style flanged clamps on all flared turbo and exit connections
High grade clamps for a solid seal and no leaks
All hardware included 
 
SPD uses EPA approved federal catalytic converters but you are responsible to verify that they are legal with your state and county laws.