What is the most you can port the stock throttle body and stock intake plenum?

 

They did a write up on that and they said its not worth the time and effort. A fully ported TB and UI only gives yyou 3 to 5 more hp whereas a 75mm TB & UI can give you say 10. Itll never be enough to make it worth it but i guess it wouldnt hurt to smooth it a little. . .