Well I took a more bizarre approach. I saved a copy of the original .kn5 to a safe place and then simply deleted all the objects mainly trees and pines very far away from the track (world_ext objects). I was careful not to interfere with other objects or meshes around the track merged with the nearest trees, grandstands, cranes, etc. That did it, I had 115/120 fps with 24 cars when in past days was struggling with 55/60 or less and lots of micro stuttering. Also I limited some LODs in CSP, that helped too.might be easier to use CSP and reduce the LOD on many things
examples:
[SHADER_REPLACEMENT_...]
ACTIVE = 1
MATERIALS = ? ; eveything
MESHES = ; use meshes as well
LOD_OUT = 800 ; limits all things to 800m, anything farther than 800m from you will not render until you are that close
[SHADER_REPLACEMENT_...]
ACTIVE = 1
MATERIALS = TREE?, shader:ksTree
LOD_OUT = 500 ; limit all trees to 500m
another example is if there are many small things let say in the pit area, if you only see them when close to the pits, limit them to 100m or so.
Using 3dsimed to look at the map and choose things, copy the name etc is easier than using Object Inspector
hope this helps
Anyways, I have yet to see some other ways to do it. Thank you for all your advice.