Before embarking on my Savage Rifts campaign (my most recent in-person game), I ran a Savage Worlds conversion of Eclipse Phase. I fell in love with the world of Eclipse Phase, but the game system was a bit much for me - too much crunch and detail for my players to learn or for me to enjoy running. But Savage Worlds can run anything... theoretically. The trick was how to capture the Eclipse Phase world in the Savage Worlds system, and the first and biggest thing I tripped over was morph vs. ego.
In Eclipse Phase, player characters are defined by the combination of their ego (consciousness, mind, etc.) and their morph (actual physical body), which could be a virtual entity, a cyborg, a biologically engineered lifeform, or a robot. Pretty much every capability and statistic in the game is a reflection of the combination of those two factors. To make life even more interesting, switching from one morph to another is, if not routine, at least common enough to assume that players will do so more than once during a campaign. For example, the most common method of interplanetary travel involves "egocasting", uploading the mind in one location and downloading it into a new body in another. So if your party is exploring the solar system, odds are they are changing morphs to do so.
My challenge, therefore, was to figure out how to reflect this core concept of the setting in Savage Worlds without breaking the system or bending it too much out of shape. You can see what I did here, but in essence, I doubled up all the Attributes for characters. You have one set for the ego and a different set for the morph, and you combine them to get a final set of Attributes. I shamelessly borrowed the idea of "residual self-image" from The Matrix here. Your ego has expectations of how strong you are, and if your morph is out of synch with those expectations, it affects your skills and your abilities. You can't necessarily access all of the strength of a more powerful morph; however, you potentially have some benefit anyway.
What this design decision does is return the Savage Worlds system to status quo with a minimum of finagling and calculation. Except when you switch morphs, your character has exactly the same capabilities as any other Savage Worlds character. When you switch morphs, a minute or two of calculation gives you all your new Attribute scores and skill bonuses or penalties. Even better, you can "grow into" better utilization of your morph by spending Advances to increase the Attributes of your residual "ego self".
One obvious question, especially to those not familiar with the setting, is why Smarts and Spirit would be affected by morph-swapping. The short answer is that the ego is like software to the morph's hardware - just try running Call of Duty on a 1980s TRS-80 and see how far it gets you. The ego can be brilliant and still handicapped by the processing power of the morph.
Generalizing from this experience, when adapting another game or another setting, the crucial thing is not to break the system you're using. If I were adapting Eclipse Phase to, say, GURPS, the approach would be completely different. For the adapter, the key requirement is understanding the mechanics of the destination system and the key flavors and elements of the orginating setting, and marrying them as elegantly and simply as possible.