I think what he's asking is how to shut codes off on efi not how to do the exhaust itself. If you saved your stocktune and deleted your dpf and are getting dtc use your scan tool to get your codes write them down and go into your stock tune and use the search button above engine calibrations. Punch in the codes and change the bar to I think no mil reported its at the very top of your options do that for all the codes that are dpf related then save tune and reflash.
06 lbz cclb all stock
07 gmc lbz ccsb
More aftermarket parts than oem parts