I do the following, and virtually *always* have perfect results....
Export Options:
Version: R2000-2002
Fonts: True Type
LineStyles: Solidworks Custom Styles
Custom map SolidWorks to DXF: YES
Dont Show Mapping on each save: YES
1:1 Scale Output: YES
I also have made up a map file, which doesnt so much have
anything to do eith the quality of the export, but merely maps Solidworks entities to individual colors/layers in the acad drawing. Cut the following text out (not couting the lines that say "Cut here" and paste them into notepad. Save the file, then point your map file to the file you saved:
'----- cut here ---------------------------
[Version]
SW990001
[Layers]
0 = 7, 0
DEFPOINTS = 7, 0
DIMS = 1, 0
CENTERMARKS = 8, 0
SECTIONLINES = 9, 0
BILLSOFMATERIALS = 0, 0
CENTERLINES = 10, 0
DIMENSIONS = 251, 0
NOTES = 0, 0
GEOMETRY = 7, 1
[Entities]
Geometry [0] = BYLAYER, BYLAYER, GEOMETRY
Notes [2] = BYLAYER, BYLAYER, NOTES
Center Marks [4] = BYLAYER, BYLAYER, CENTERMARKS
Section Lines [5] = BYLAYER, BYLAYER, SECTIONLINES
Bill of Materials [12] = BYLAYER, BYLAYER, BILLSOFMATERIALS
Center Lines [14] = BYLAYER, BYLAYER, CENTERLINES
Dimensions [1] = BYLAYER, BYLAYER, DIMENSIONS
[Colors]
' ---- cut here --------------------------
if you like the results, I have a macro for you that automates the whole process from export out of SW to import into acad.