I doubt that you need a new turbo...Get yourself a EGT and Boost gauge. You'll see how much boost you have on a daily basis and can tell how long you need to let it cool before shutting off the engine...A few WOT's from time to time certainly help

__________________

7.5 3500QC 6.7CTD 68RFE Build date June 2007
Superchips tuner 3808, Boost/EGT Laser Gauge, Airaid cold intake