The V6 one is lighter and they had a run that had an imbalance problem that led to the catastrophic failure. The factory speed limiter on the V6 cars made this a non-issue, until people started turning that off in tunes.
The V8 ones don't report any problems, even at very high power levels. Don't underestimate the 2 piece. Other than the driveline lash annoyances, it's a stout piece.
2014 Premium GT, SGM, Brembo, Auto, Tech, Comfort, etc. GT500s, Steeda UCA, VMP auto tune, 100 shot on BBR tune, best et: 11.38 at 120.85
2012 GT, Candy Red, Brembo, 3.73, Tech, Comfort, etc. Procal tune, Roush upper, UMI LCAs, Steeda red bracket, GT500s, 28X10X16 Hoosier slicks, best et: 11.91 at 115.23 RIP