This questions is really to vague.
General rules of performance optimizations applies. And since you use Fuse SF (Apache CXF) then look for how to optimize WS/CXF as well.
Its actually we are trying to implement a cloud based WS architecture based on FUSE Service Framework where we want to host multiple services to act as an integration layer for business components running on different FUSE products. So in that case would like to know for such architecture if at all we can have some configuration based parameter in FUSE Service framework/Apache CXF itself in addition to optimizing the WS.
It really depends on what's you want, there are some configuration options on choosing different transports other than http.
If your service want's to talk to each other locally in the same JVM, you can chose local transport.
You can deploy the FS endpoints into the Fuse ESB and use nmr transport to integrate the services.
Just my 2 cents.