Well, a fun cheat I found, well, not really a cheat, moreso a bug, is if you want an explosion proof, bullet proof, crash proof firetruck. Do a fire mission, extinguish the car, then do the instant replay all the way up to when you extinguished the car and let it finish running the replay. At this point, wait for the money indicator to leave the screen, then press F1, it'll instantly give you cash and time for a fire mission you never did. You just keep on waiting for the cash text to the leave the screen and keep hitting F1. It adds time to your fire mission timer and then you can run around the city in the firetruck ramming cars off the road, smashing into EVERYTHING and not exploding. I had my timer up to 40 minutes and I just ran around the entire time smashing stuff. As soon as the timer wore down, I would just hit F1 again to add more time. Instant fun.