The Model S is already modular in many ways, but one way it is not is with regard to the main wiring harness. Well, that's my understanding anyway, and is one of the reasons that adding auto-pilot to pre-auto-pilot vehicles is prohibitively expensive. This lack of modulation in the "mains" of the vehicle are one of the reasons we are considering leasing the X. I would prefer not to purchase one of the early models, only to find out 2-3 years down the road that we can't add on some awesome new feature because the vehicle isn't "upgrade-able." Of course, this is simply one of the prices of early adoption, but what if it didn't have to be... Perhaps one of the features that is being kept under-wraps is greater modulation. So, if new sensors, or a new advancement, that would be difficult to implement in a traditional wiring harness design would no longer be as great of an issue. This would mean that you wouldn't see such drastic depreciation when new features are released/added to newer models. I'm not that familiar with modular systems, and the ways it may be difficult to implement. However, if you consider that these cars are more similar to rolling computers, then I think it makes sense to make them as modular as possible. Because we all know what happens to the value/usability of our phones after only a couple years. And one of the reasons Google has been working on a modular phone design. Anyway, just a musing I had, and am interested to hear thoughts on the idea. If this has already been speculated, I apologize, but a quick search of the forum didn't reveal this specific suggestion.