Landclass doesn't affect the colour - only the chosen textures do that, so do you mean textures?
If so, Adam Mills European textures from Avsim are far more realistic than the brown that covers Northern Europe in MS world, so you might want to grab those - they're free! In terms on Landclass, I'm currently using the one from UTX Europe, which are more accurate than the Scenerytech one and vastly more realistic than the default. Antrim no longer surrounds Belfast Aldergrove, Wombourne isn't connected at the hip to Wolverhampton and Dudley and Shrewsbury is in the right place, if not the right shape... None of the autogen is particularly accurate, but it's a better start.
Ian P.