There is, if you don't mind cheating your butt off with this GTA 5 "trainer" created by LinGon. Once installed and activated in story mode by using the Home key, it provides your trio of bad boys with a number of hotkey cheats, like infinite health, stamina, oxygen, and ammo, super speed while running, and even partial immunity from wanted levels (if you mess with the cops directly, they may still come after you). You can also teleport around the map by using waypoints instead of having to do all that pesky driving. While I imagine it completely removes the challenge from the game, sometimes you just want to go completely nuts without suffering the indignity of a brief hospital visit.