the factory rubber bump stops are a much harder durometer and really aren't designed to handle what any truck needs when "airing it out". They are designed to deter metal to metal contact.
Helio Muiro tried not doing bump cans. Now while he didn't tweak the frame as many gen1 owners did, he did deform the frame rail to the point that the bump frame didn't fit properly once he went to install real bump stops.
At the end of the day, If you are shying away from spending the $1500 on the bump kit, it might not be a great idea to jump the truck at all. This hobby is expensive. You have to build the trucks properly to keep you, your passengers, the spectators, and the truck safe.
Buying the actual truck is the "cheap" part.