Always planned to use a good strong Guard on my Car, consider it essential for any "serious" Trials events...
Left it off one weekend, did a minor Motor Club Field Trial, nothing too taxing, but following that event started to have MAJOR Gear selection problems...
After weeks of fruitless investigations, finally had to remove entire Engine & Transmission, completely strip Gearbox down to discover the Rod Selector Outer Barrel/Detent thingy completely split into two pieces!!
You then end up managing to select TWO Gears at once, which means that when you drop the Clutch to pull away, the Engine stalls, as the Gearbox is effectively locked solid!!
Worked out that the weight of the Car and it's passengers landing heavily onto it's unguarded "Shepherds Crook" Gear Selector Rod is enough to break said Gearbox internally!
Unfortunately, you can only replace this part, once busted, by COMPLETLY stripping the Gearbox & Diff unit, ie; Diff AND 1st Motion AND Third Motion Shafts, with ALL the Gears out of the Casing!!
Its a real pain in the backside, you have been warned!!
Therefore personally, I consider a good strong Sump Guard as ESSENTIAL if you use your Buggy off road.......