I would have to say most of us run DSS Level 5 Halfs...I believe that you can get them from some of our vendors. I got mine from 402 Performance.... http://www.srtconnection.com/forums/forumdisplay.php?f=194
You can buy the '09 upgraded halfshafts/hubs for the stock SRT8 rear end for about $500 shipped to your door. Contact Jeff at allusamotorsports.com. These haven't been around long so they are relatively unknown what horsepower they can handle. They are 32 spline vs. 28 spline on '08 and earlier halfshafts. The hub end is thicker and that is where the pre-'08 halfshafts appear to break (I know mine did).