The decision is up to you on whether or not you think you need to replace anything.
The AFM/DoD failure is a very common issue among the 2005-2008 grand prix's/impala's/monte carlo's/buick allures and they used this same early design with the 2005-2008 Trail Blazers and Envoys with the 5.3's. Heck even the early 5.3's from 2007-2009 in the half ton trucks suffer from possible failure and oil consumption issues.
If you have no abnormal noises and you are just fine with keeping the AFM/DoD active then nothing has to be done. If you want to slow down the oil consumption then disabling the system with a custom tune can do that. Or if you want to remove the system entirely that would require replacing all lifters with new regular lifters, new NON DoD camshaft, new cam gear, remove and replace the valley plate with a non AFM/DoD plate, new push rods, new head gaskets. Other minor odds and ends with a camshaft swap then a custom tune to round it all out.
Generally people that don't hear much about don't work in shops that repair this stuff often or they don't work in the aftermarket that hear of this stuff all the time. Tons of engines end up being problem free and a large handful of the thousands of engines out there suffer these types of failures.
