8m is too much indeed. I was planning to model a steampunk beholder which had mechanical boosters and stuff. I prepared the high poly an zbrush and imported it into maya. My plan was to make this 8M polygon to a low polygon object at the end with a plugin called nex. It helps you to retopologize your high poly model to a game object.

Thanks for your reply. I think im doing things wrong at the grouping, combining and hierarchy. I combined all my parts to get a single and deleted history. I am confused at this level. When i combine and delete history, combined individual parts still keep their own histories? What does grouping help ? Combine or group? whats the difference... Thats why i think i need a source to learn the aspects. I know the techniques to visualise but like a 3 year old kid drawing good pictures but in a messy way....