i know the newer cobra problem is due to a returnless fuel system. i only had one problem with my 5.0 car. it was my fault, got the itchy finger and sprayed at too low an rpm.
but wet kit and NX is the way to go.
use a dry kit if you want to have problems. cause u'll have to get bigger injectors, diff mass air meter, possibly bigger rails. and it will be even more fun to tune