When working on my 99GT, it had the fuel pressure valve on the fuel rails. During the installation, I over tighten it and snapped the NX connector off . I ordered a new fuel rail and did not come with the duel fuel lines and no adapter. So, I talked with the guy from Ford and he stated that new fuel lines do not come with the pressure valve and a single cross over for the rails. He stated that i should tap the cross over line and put in a T adapter in, which sucks. So, i drilled the NX adapter out and went to home depot and purchased a brass adapter for it (which worked). I have additional single cross over fuel rail with the electronic adapter sitting in my garage...so if you try to tap into the cross over and mess up, i willing to get rid of it for cheap the only other option is to find one from 99-2000 GT or junk yard it. Good luck
If you are going to get the "T" adapter, get it from Moroso. It is an aluminum adapter with a nice blue colot. It will give your engine bay a nice touch. The one from Home Depot is made from brass and won't look good.