[wingnut60]

I won't get into the weight situation with your 350--I had one and certainly understand why you want improvement in those areas. Are you out of warranty on the engine--if not, the power enhancement will probably void what you have left.
I can tell you that if you 'chip/tune' the engine, and even if you only use the towing mode, you will probably stretch the head bolts, leading to head gasket failure. 27K+ is a lot of gross weight for a 6.0, even if you have the Tow Boss option.
Can't address the value of the brake addon--but I never had to replace the pads/rotors on my '07 dually after 95400 miles of driving/towing with the same gross weight.
Joe