This is my first foray into buying a Mustang. I’ve whittled things down to a couple of different models, but still searching. I came across a ‘15 GT Premium that has characteristics of Equip. Group 401A, but it’s listed as a 400A. It also has a small dashboard plaque that says, “GT350 R/Chassis TT007. It’s definitely not a GT350R, nor is it a GT350. As it has the 5.0 in it. I haven’t seen that in my search before, and haven’t found much info about it elsewhere. Is that a preproduction/engineer testing car, or something like that? Also, what are some thoughts on an ‘18-‘20 GT w/GT Performance Package Level 2, and that MagneRide suspension? Thanks!