The beams and springs would be the subframe. Guess it's fixed in the back?
Pretty sure the frame is an open C and designed to torsionally flex a lot, but the suspension is probably pretty solid if you have it loaded less than it used to be. If you can cross a ditch at an angle so that a front wheel and opposite side rear are both in it at the same time... and you are teetering on two wheels, then that should be "worst case". Take pictures please! I'm interested in how the mounting system behaves.