Merc/Rebel Walker, and thanks Arjun

Hi guys, firstly a big thanks to TMP member Arjun Choong, he saw some of my previous walker conversions and liked them so much he sent me a spare Kolossus, we talked about a swap but I didn't have anything he needed, he is making a Star Wars droid army out of the Star wars collectible figures using Battle droids #28 and #30, I have looked in the local stores with no luck, if anyone reading this post has any spares I'm willing to buy or swap for them, and will pass them on to Arjun.
So onto the Kolossus, wow this is a great model, it is a really good size for 15mm, I wish I had 2 or 3 more of these (anyone with spares, I'm willing to swap or buy for more) it will be used as the center piece of a mixed race mercenary/rebel army, it will be made up of Felids, Humans, and CMG mixed alien mercs, should I leave it with this paint job (its pretty nice, but links it to its original origins) or should I paint it? not sure what colour scheme I will make this army, any ideas? I don't think I will convert it in any way, it is to nice as is.