I have the same intake on my adapter. Since I tend to over think things, I was concerned the intake might be under some stress and completely removing the underneath part might release the stress causing the manifold to become warped. So I left some the under side in place. To add to my concern, when I made my V cut on the front side of the intake it popped a little when I got right to the end of my cut. I used a combination of a hole saw and a cutoff wheel on my angle grinder to get my desired cut.