Driveshaft help
 

Long story short, replaced my carrier bearing a few thousand miles ago and im now getting a vibration under my seat at high speeds and acceleration. u joints seem to be okay and slight play in rubber on carrier. My truck is lifted 6 inches with stock shafts. Would i be better off buying a new one or even one piece? Looking at driveshaft specialists of texas. They claim their best aluminum one holds up to more hp and torque than a stock steel one? any inout would be appreciated Thanks.