so my questions are: 1) is the stock baffle in the valve cover removed? or is just the shell of the valve cover drilled? 2) ive seen setups with two bungs welded in the front. two in the front and one in the back and one in the front and one in the back. what is the purpose of the extra vent and how is it beneficial in relation to location of the bung? 3) what is the best size for this? -8.-10 or -12?