The 2006-2007 GM Duramax 6.6L LLY and LBZ are the best of the best(8th Digit of the VIN number will be "2" for LLY and a "D" for LBZ).  This is the Duramax that every one is looking for... Pre emissions, 6 speed Allison, stronger rods and no DPF.  The basic difference between the LLY and the LBZ is horse power, the LLY makes do with 310 hp and 605 ft/lbs., while the LBZ is stronger with 360 hp and 650 ft/lbs.  These two motors are identical, so any part that fits a 2006 LLY will fit a 2006-2007 LBZ Classic.  2006 was also the last year to row your own gears, the ZF-6 - 6 speed manual truck went away for 2007.