I don't agree with much of the statements here on how to make a 200-series handle better.
While she'll always be a pig on account of the weight, the 200-series has respectable suspension geometry to actually put up descent traction and hold a corner. As several have mentioned, the LX570 with AHC suspension might have better suited you better as it has an uncanny ability to provide solid ride and body control for sporty handling, while also adding to it's off-road ability.
It would be useful to understand and get specifically to what part of the handling you want to improve? Body control? On-road traction? Handling "feel" with a stiffer ride. All the above?
Tires, yes, but firmer riding and lower traction all-terrain KO2s would not be my idea of adding any real "handling". Perhaps that may be what you're looking for as some have suggested.
Generally, one can improve handling with more spring rate and damping. Upsizing wheels to a degree can help. A better tire with better suited compound to the surface and weather in your area. Understanding that some of these changes may compromise your experience elsewhere.