Has anyone looked into doing this before?
Do our heads have much room for improving air flow efficiency or volume?
What else would need to be changed to accommodate such a modification? Larger valves, custom cams? Is it even worth it?
It’s doubtful, the S4 heads were designed pretty well and JHM did some testing, but the gains were not worth the money, even with aftermarket cams…I’d assume the same considering how similar the RS4 is to the S4 or vice versa.
Port matching may help a little, but you also have to remember you can potentially hurt performance with a port and polish if you take material from the wrong place…unless you are going to have the heads tested and go through multiple revisions.