More damage - simple. use the LUA function : PedSetDamageGivenMultiplier(gPlayer,4)
gPlayer - name of the player, dont change that.
4 - How much to multiple the damage. 2 to double it, 3 to triple and so on....
Reversing busting - Bind 1 of your buttons to a action node of reversel or any attack, that way when a prefect/cop come to bust you, you press the action node and he will countinue the busting animation while the player wont get busted, he will do the action node and you can run away.