Regarding the color version download, I assume you're referring to the film's availability in digital format. The Human Centipede 2 (Full Sequence) was initially released in black and white, but it has since been released in color as well. If you're looking to download the film, I recommend checking reputable digital stores or streaming platforms that host horror content. Some popular options include Amazon Prime Video, YouTube, Google Play, and iTunes.
The practical effects, particularly the gore and "medical" sequences, are significantly more graphic in full color.
Always support the creators by purchasing or streaming through official channels. This ensures you get the best video quality, the full unrated cut, and a safe viewing experience without the risks associated with third-party downloads.