I'm skeptical. The BioWare devs said they changed video cards when testing Mass Effect and didn't run into any activation problems. However, after it was released, I saw more than one report on their boards where poepl found that changing a video card burned an activation.
My own experience with BioShock was that adding a hard drive (not a new one for the OS, but just another internal HDD for more storage) triggered an activation (in fact it locked me out of the game).
So, while they say you'll be able to change one component, I wouldn't count on it. Quite frankly, I;m not confident anyone but SonyDADC realy know what will tirgger an activation - and I wouldn't be surprised if even they didn't know for sure.