AmazingRC.com

I am working on a project using a Losi High Roller rc truck. I am mounting a platform on it along with some other devices. I have the springs tightened all the way and with all the parts added to the platform the truck bottoms out. I checked with the people I purchased the truck from and no stiffer springs were available. What are some methods to stiffin my suspension and prevent my truck from bottoming out?