stock 5.0 vs chp

CHP=Coast High Perfomance? Probably completely different internally if that's the case, with the block being the only part that's the same. Maybe the lifters and oil pump, too, but I wouldn't think much else.
 
As far as the engine goes there is no difference between an SSP and a regular 5.0 Mustang.

SSPs have a SSP specific alternator, blue silicone hoses, reenforced seat mounts, I believe a PS cooler, relocated trunk release and the interior dome light doesn't come on when you open the door.

Performance wise they are pretty much the same as a LX 5.0 coupe.