Without other mods to actually increase the potential of the engine, ie more displacement, higher compression, more cam etc. There is nothing to be gained by an average porting job. And I mean nothing. Having tried this, using a flow bench I was able to make some gains in the intake and exhaust ports. However the rest of the engine's design is so mellow that there was no increase in output. I ended up increasing displacement and compression with a better exhaust and hot cam. This did help!
Chris