When thinking about the phrase "in Christ", the image that Christ potrays in the Bible of the vine and the branch come immediately to mind. He is the vine and I am the branch. I abide in Him and He abides in me. As long as I am attached to the "Vine", I receive substanance. In Christ, all things are possible. If I try to respond to something in my flesh, it never works. However, as I seek Him, His Spirit directs, counsels, warns, encourages, teaches, ministers.... about all things because He resides in my heart.
My earthly father is now deceased but when he was alive there was one day at work when his skin was accidently burned with acid. He had to have the affected skin grafted. The doctors took skin from another part of his body and grafted it - somehow molded it to the wound and made it look brand new.
Likewise I am having my affected area (sin) grafted as I am "incorporated" into Christ. I am being transformed in to His image. My old man has passed away and my new man is being transformed. It does not mean I am perfect because I am so far from that. Only God is perfect.
It does mean I am changing much like a caterpillar in a cocoon (in Chrysalis form) and when I get to Heaven I will emerge as the beautiful butterfly that He created me to be.