If you haven’t read the first two installments of this article you might want to start there.
I have gone ahead and converted a Ellyrian Reaver into a Centigor. Since, I am not very artsy I am quite happy with the result. I even think it is a better representation of the what I believe a Centigor should look like than the actual models. Below I will give you the step by step instructions that I used followed by a gallery of photos.