what is the point and do i need to have the excess.

 

If you have a properly setup and sized BOV, you dont need two unless you run very high boost, alot of show cars have them, such as Adam SHOWruwatari, because it's something else you can polish, and its going overboard, or showing off. If you run very high boost, then one BOV might not be enough to bleed off the pressure, but if you are to that point and are running 35-40psi , you have enough money to buy turbos to the point where you probably dont even run a BOV. BOV's can acutually hurt performance by creating a leak in the IC piping, if its set too soft, it will create lag between shifts, and if it set too hard, it will put pressure on the compressor wheel when the throttle closes, you have to set it to a happy medium.
Rob
93 RX7
Undergoing Garret T-72/haltech/big port