I sold my blanking plug for about £10 as for chatter its not something you can make happen, it only happens now and again when you get diffrent pressures building up. so keep your stock bov where it is.On the intercooler pipe you will have a black rubber pipe comeing off and going into your stock bov.unplug that and use it for your greddy bov then unplug the vacuum pipe from your stock bov and conect it to your greddy bov if you get me lol so realy your stock bov it acting like one of them blanking plugs, all you should be left with is the cam cover breather going into the stock bov nothing elss.Thats why i said you will need to cover the stock bov with something cause you have unpluged things and it will be left open. like i have said im not to good at explaining things someone elss might be able to shed abit more light then i am at the min ;)