Does every Mustang have a vibration point?

[Killercanary]

My weight has been off for a long time, as well as the 25lb weight found in the passenger side fender well on SN95 convertibles, the shake is the same now as it was then. It almost feels like I have a bent or broken radial, but I don't know. The insides of my tires wear prematurely and I thought this was the problem, I had the alignment checked and it was perfect, so I still don't know why the tires are wearing like this. The suspension is 100% stock too. It only occurs on the inside tread though, not inside and outside so its not an air pressure problem. Like I said above though, it seems like at times its worse than others, almost like its the worst when I first start driving, then after while it gets better, but still does it. I need new tires anyway, so hopefully when I replace them, the vibration will be minimized.