Oh I understand so with the top piece mounted on there is no exhaust for air to escape aside from the back of the case. But I see no reason the top would stay on the case if I am gaming, or be there anytime if I sit my chassis on my desk instead of ground. Anyway I don't think I have to worry much about dust filter since I will use top fans as exhaust.
Thank you all for your helps and inputs! all of you guys helped more than you can think