OK, I know it's been a whiles' for you triple bump folks, but I recently completed swapping the JTV 59P bridge with a Graphtech wraparound bridge. Kind of good and bad.
The good. The new piezos are GORGEOUS, there are so many tones you get with the Graphtech that you don't hear with the stocks. Particularly the acoustic sounds. Evey better if you roll back your firmware to 1.71, lots of discussion on that, but I really like it.
The bad. the bridge doesn't fit the existing posts, so you have to remove the stock posts, slightly enlarge the holes, and install the new posts. Be REALLY careful when removing the posts, you'll need to score the surrounding paint, so you don't chip it off (which I did, ugh.) Then, the hole spacing is not quite wide enough, like fractions of a milimeter, so you'll need to dremel the new graphtech bridge to get it to fit. And the last "bad", since the new ghosts are SO sensitive (you have to reduce the string volume to 10-20% of what the stocks were), somehow, it really messed up the custom tunings. Also, since I am back to v1.71 firmware, you can't do the custom tuning in the software, just with the guitar itself. What happens is you get this odd "warbling" effect, almost like a 12 string, but is completely unacceptable. I've been able to program in acceptable -2, -1, and +1 capo custom tunings, but anything higher warbles like crazy. So in effect, I've had to give up the custom tunings, which is too bad, I really loved those. But it sounds SO good, I don't think I want to try to go back.
Line6 says the warble comes from out of adjustment mag height, albeit when I asked, I didn't tell them I did the ghost install... ?!? (didn't want to get scolded.)
Looking backward? Not sure I would have done it. The stock sounds were "OK", and might have been better if I rolled back to 1.71 with the stock bridge, and I would have kept the custom tunings. But now that I have it installed, I really like the sounds, and it would be extra hard to re-install the stock, so I'll keep it as is with the ghosts for now.... .