It looks like the cheats can only raise your warrant level to five stars. Even when you're just blowing away Feds left and right, and shooting down copper choppers, you still can't get the sixth no matter what.
Do you have to open it up by doing a mission of sorts? Do i have to mow down military people at the base (in Vice City of course)? I want to be the most wanted criminal in VC, but it looks like i can just be nothing but a petty theif :-(
You have to complete the mission "Sir, yes Sir!" for Cortez. (Or is it Avery? I can't remember.) After completing said mission you will be able to obtain that elusive 6th star. One fact to remember about the army: You will have better luck running from them on foot, just keep you distance and try to avoid having a tank roll over you. Enjoy!!
"i dont know what it is or what it could be but i get a woody when these pussies try to push me thinkin they gonna put me in a position to pickle me y'all tickle me pink i think i'd just rather have Pink Tickle Me" Biggie, 50 Cent, Eminem "The Realest" (RemiX)
If you've beaten the main storyline, then grab the Hunter copter from the military base, and just go wild - use the missiles, shoot down other copters, shoot down the banner-trailing planes, strafe traffic.