Thanks for the input.
I was not totally compairing the P.S. and Cummins and at this point they are all I have to go on,speaking of the smaller diesels.
As of now I know nothing about the Duramax LMM except the spelling.
And any of the dealers/service/parts I have spoke to seems to know less than I do,other than saying it is a good engine.
Heck all of them say that,about there products,and I learned the painfull way with the P.S. 6.0.
2007.5 GMC Sierra 3500 BLACK SRW C.C. 4X4 LMM/Allison,long bed,Loaded,Westach EGT/Boost pass side, Edge Insight CTS EGT driverside, DIY stock airbox mod, aFe proguard 7 OEM airfilter. Back-up sensors + Back-up camera tied into the navagation screen, Redi Lift leveling kit, Cognito UCA's, Pitman Idler arm support, AMP Power steps, Firestone Air bags with controller in cab.