Well, I am sure they may not be neccessary but the Forge BOV that I installed seems to work quit nicely. It does keep my boost up better between shifts. And the added extra benefit of everytime I pass a V8 and shift they get that lovely sound of the H4 sighing. It is just weeping for those unsuspecting victoms. And my advice on the boost controller go with the Greddy Profec B. More money but well worth it if you are looking for more realiable power. Have fun either way. Z