You can set your buggy up to handle really well on grass and not roll over. Half of our championship races are on grass tracks, so trust me I know.
Get some Medial Pro Turbo tyres or GRP Grip to start off with. Then use the stiffest springs and sway bars available for your buggy and fill the shocks up with some 450-600cp oil, with the rear about 100 thinner than the front.
You'll also want about 15'000cp oil in the front diff and 20'000cp in the middle diff. Ride height should be suspension arms level or a bit higher depending on the height of the grass and whether it slows the car down much.