6g74 GDI Vs 6G75 Mivec

I have an 01 Galant. (3.0 V6 GTZ) I've been research and research, now I want to know which of these two GDI or Mivec, would be the easiest. I read somewhere that they can be combined not to sure what the person meant by that. What bolt-on mods can I do to my 6G72 right now, and would those bolt-ons fit on the GDI/Mivec? Not quite sure what the normal 6G74 can pull, haven't done much research on it, unlike the GDI/Mivec pulling around 260hp, (I think).Lol. Generally just some advice on these engines, if I can't get any advice I'm probably going for something better, I just love the 8g Galant and don't want to get rid of it.