How can I bring STAG back if I have 100% completion?

There's a couple of the Saintsbook challenges that require you to have STAG forces available to kill. After you complete the game, however, the STAG forces are nowhere to be found. I believe that you can fight a few more STAG forces if you replay the final mission, but I think my save is glitched, so that's not an option.

Is there any way post-game completion to bring STAG back? I miss their much nicer tanks and VTOLs for hijacking :(

Solution 1:

There is, but it depends on the progress you've made on Vehicle Thefts. If you haven't yet stolen the VTOL Condor for BJ Barnes, start that activity. That should spawn STAG troops in the park around the VTOLs that will magically appear there. Instead of running off with their precious little plane, just hang around and remove the forces who are blowing it up protecting it.

Solution 2:

You can not get STAG back unless you get DLC (for XBox 360) and you get STAG homies (STAG commandos only). They will not drive STAG cars, but you will have STAG homies.