Greetings Luis. I'm glad to see you have an architectural background as well. What CAD programs have you used so far? AutoCAD? SketchUp? REVIT? If you've been using 3DS Max for that long, there's an exporter for Max which I've used for years. If you're looking to get started in Blender, perhaps we could arrange a date and time for lessons over IRC.
Raven's comment is, I believe, directed towards your comments on the Colossus, and not your own work on the Rakshasa (i.e. don't fret about converting the Colossus just yet, focus on the modeling/texturing of it.)
I agree that this is going to be one of the heaviest models in the engine, probably the heaviest of all, but remember that there will only ever be one in the mission at a time. All the greebles you've seen so far are going to be either detail-boxed or normal mapped. Further, the whole thing will be UV-mapped, and so will actually use less memory than the existing Hecate or Orion models.
Aside from the aforementioned hangar, I've finalized the geometry. Currently I'm working on the slow, painstaking process of unwrapping the model for texturing. This process alone can take over a year, as Vasudan Admiral's Hades can attest to. Once it's unwrapped, one party can paint the texture while another prepares it for conversion into the game. By the time this actually makes it into the Media VPs, we will be at 3.6.11 and you'll probably have an upgraded computer.

The Colossus
does have over 80 weapon turrets; look over its table entry to see what they are.