well I saw that in rich´s tech section and left my rg´s neck straight as an arrow, but he says that he leaves some relief in the neck, so whats the difference? can you get lower action with some relief?

Every guitar is different. If you have the setup you want with no neck relief I say leave it. You might be able to get your action slightly lower by giving slight relief. I had a neck once that was fretting out really bad (straight as an arrow like your neck), and the relief took care of the fretting out problem. Now I can bend all day and the notes won't go dead.

my action is not high but it isn´t like super low like in my sg, but I like that I can pull the bar all the way up without the notes fretting out, so if I leave some relief is it posible that I will stll be able to pull the bar without fretting out with lower action?