The higher the resolution ( in terrain editor ) the more polygons used to create the object. What I would do is evaluate each one. If the object is close up or has much detail you may need a high resolution. If you can't find any way around using high resolution try this. Whenever you import or create new objects, go to solo mode to work on them. ( solo mode is the blue button, at the bottom, in the middle of the VCR type buttons, selection palette mode ) Select the objects you will be working on then click the solo mode button ( it will turn red ) then those are the only objects present in the scene. Which should speed things back up for you. An example would be say you import a flower, select it and go to solo mode to texture it. Then when it's time to place it, figure where it will go, go out of solo mode and select a few object in the vicinity ( along with the flower ) then go back to solo mode and use the other objects as your guide.

Stephen Ray