the X pipe ain't your problem---walk around the truck 10 times (5 in each direction, switching directions every couple circles----------
Look at the exhausrt system from the back forward instead of front to back-------
the most fab problems for exhaust systems are at the rear---look at any current vehicle
Its a truck, how about side exit forward of rear wheel ?
How about round muffler with angle to the inlet/outlet?( gets rid of problems with large flat ovals and straight I/o)
How about moving the cross piece for the shock mounts forward of the rear end (like they used to be before coil overs)
Once again I'll mention that the exhaust systems from the pre 2005 mustang will go up over the axle and then out rearward under the frame rail member---take a look under the mustang (not Cobra with irs)
You can get oval mufflers with inlet/outlet both on same end which is nice to do a side exit in front of rear tire
But in any case, change where your standing looking at the vehicle and reverse your thinking-----you know what you got for the exhaust manifold, now decide what you want for an exit tip---round? oval? polished?
Damn its cold here and on the way down