Well ...
First off, their GAWR numbers are wrong - just look at the placard on the door jam of any 200 series Land Cruiser:
Front GAWR is 1630KG, not 1800KG.
Rear GAWR is 1950KG, not 2000KG.
As stated on the placard, this is with the P285/60R18 tires inflated to 33psi Cold. That gives us a Load Limit of 2512LB (1139.4KG) per tire -or- 5024LB (2278.8KG) per axle.
According to design criteria, the tire Load Limit should not be less than approx. 117% of the GAWR. Toyota's design has the Front Load Limit at 140% of the Front GAWR, and the Rear Load Limit right at 117% of the Rear GAWR.
What we need to be concerned about with wheel Load Ratings, is the 2512LB (1139.4KG) Load Limit number. At 2250LB/Wheel, as Black Rhino state, the 18" Madness wheels do NOT meet the requirement.
Simply put, if you inflate your stock P285/60R18 tires to the Recommended Cold Tire Inflation Pressure of 33psi, you have exceeded the Load Rating of the 18" Madness wheels. No bueno!
But, as I have stated before, your ride, your choice. If you choose to believe a company that can't even get the GAWR numbers correct, what faith can you objectively have in their other numbers?
Caveat Emptor
HTH