The EBPV removal was easy. I found a thread hear that explained it. When I removed it, I had replaced the exhaust and intake at the same time so I dont know how much of a diff it made. But if you pull your down pipe off and look at it you'll understand why people remove it and it has to make a diff. you might as well shove a rag in your pipe it takes up that much space
It has got to make a imrovment in flow. FYI, I only plugged one side and left the other side plug and retainer in. I tapped mine with a 1/2 NPT and it required no drilling. Then used a 1/2 pipe plug.