Jaime, just so you know mate.. i set out with big plans on what i was going to do porting wise, jesus i was gonna do inlet side, headers, heads them selves.. but the more i looked into it and actually got advise from people that know what there talking about, i soon found out that i was very limited on what i could actually do that wouldnt run a risk of actually hampering rather than helping things.
My reasoning was that my heads were lightly polished and i was looking to optimise everything else so everything was working as best it could, i found it very hard for people to share information with me and it was Paul Blamire that more or less slapped some sense into me, tbh the most that i could do is what i done.. which isnt anything much more than just amusing yourself and being able to say you prted your headers your self

I have no doubt that what i have done is better than it was originally, but how much benefit it will be... well i aint expecting much.
You will need a Die Grinder and Carbide cutter, and an air grinder is cheap, but they will burn out a non industrial compressor, i melted the solenoid in mine it was on an off so much, electric die grinders are the ones to have but they are 200 euro up. I got a lend of an air one.
Be carefull on the polishing of things.. the more you look into things you will find that some say that some areas shouldnt be polished as much as others as turbulence will help fuel air mixture, creat turbulance that can speed up exhasut speeds etc etc.... It really is a horses for courses situation, everyone has there views and opinions, very few will share what they do, and no guarantee what they do is the right thing.
You are probably looking at near 1k gbp to get heads up and cnc port and polished and flow bench tested... so as you can imagine you or me with a 40 euro die grinder aint going to do much