A dry sump system keeps the engine oil in a separate remote tank rather than in a sump below the engine. It has a few advantages,
Because you don't have a huge sump below the engine, you can fit the engine lower in the car which gives you a lower centre of gravity, improving handling.
Sometimes when you go around a corner fast, the oil sloshes to one side of a standard sump, possibly uncovering the oil pickup pipe and causing oil starvation and possible engine damage.
The crankshaft never gets dipped in oil which could have an effect on horsepower.
Basically, because racecar.
Perhaps some of the 4x4/offroad guys on the forum could give you better information on lift kits than I can.