Here is my complete work through to get near perfect results
from MOI importing IGES and exporting .lwo from SW 2008 to modo 301.
Open assembly in SW
"Save as" IGES .igs
Under Options - Solid Surface features - Output as - "CHANGE TO" - Manifold Solid B-rep Object type 186.
Surface representation/system preference - standard
check box next to
Export 3d curve features
Use High Trim curve accuracy
IGES asembly structure
Save all components of an assembly in one file
Flatten assembly heirarchy
close / minimize SW
Set - options - general - to meters
Select UNIT OPTIONS
Set Default Unit system - to Meters
Select all and rotate 90 around origin - This sets my model flat and centered on the work planes - you may or may not have to do this.
SAVE AS - .LWO
I use the following settings
Divide larger than .25 curved
Avoid smaller than .01 which is around 2" on my mesh
Aspect Ratio Limit 2
Oen .LWO in modo
Model should be near perfect geometry in Modo , with each part individually selectable for materials.
I will (probably) post some renders in the next few hours.