I can attest that the Nitro and Spectrum are definitely NOT the same body/case. It's not even the curved top edge versus the square edge of the Spectrum that makes them so different. My Nitro extended battery and back cover arrived today, and it's not even close. Other than being a general rectangle shape, nothing else matches up. The Spectrum is longer. The curved top edge of the Nitro cover wouldn't even come into play if everything else lined up, as the top of the Nitro cover is one big open hole. Now, I guess the wait is on to see if someone makes a back cover that doesn't have a huge square in it. I could probably make the stock cover work with the help of a heat gun, but I'd need a spare back cover before I even tried.