Sometime after doing IRS all poly upgrade and torsen diff. and new tires and sub frame connectors I started feeling a vibration that for me as an experienced car guy has me stumped. Its kind of like a tire flat spot vibrations but it seems like i only notice it after driven a few miles and the engine has warmed up. It is mostly at 50 mph and over but some times slower. Ive had the wheels/ tires re-balanced but the balance looked good to begin with and after it didnt change. The vibration seems to come from the whole car not just the steering wheel. It is not a bad vibration but its always noticeable. It seems to be more when accelerating but not always. I can be going down hill or uphill and doesnt change. If I slip it into neutral and coast there is not much change??????. Ive had the drive line disconnected a couple times without marking the position, could it be the drive line not put back in the same factory position on the diff.?? This car has 11k original miles and the U joints feel and look good.------any experienced ideas?