I am of the opinion that the answer is NO for most if NOT all of the Contrib Plugins.
But, when I do what is necessary for the PCH version of sdk.h to be used; it seems to just as likely slow down the building as speed it up.
Patch to add the location of the sdk.h PCH file to the search path for the "ThreadSearch" Plugin.
This and the Games plugin shows the best improvements of the few plugins I tested.
Tim S.
Index: src/plugins/contrib/ThreadSearch/ThreadSearch.cbp
===================================================================
--- src/plugins/contrib/ThreadSearch/ThreadSearch.cbp (revision 9447)
+++ src/plugins/contrib/ThreadSearch/ThreadSearch.cbp (working copy)
@@ -48,6 +48,7 @@
<Add option="-DwxUSE_UNICODE" />
<Add option="-DBUILDING_PLUGIN" />
<Add option="-DNO_LOGGING" />
+ <Add directory="..\..\..\.objs\include" />
<Add directory="..\..\..\include" />
<Add directory="..\..\..\sdk\wxscintilla\include" />
<Add directory="..\..\..\include\mozilla_chardet" />