I edited your question not merely to refine it, but to make a point that might help you answer it yourself. If you closely compare my edit to your initial question (which is not badly written!) you'll see how much more succinct my edit is, and how much power and clarity is gained by that succinctness. My point is that you tend towards hesitation, uncertainty, and waffling; you throw in unnecessary qualifiers to the point of obfuscation. Get to the point when you write. Notice how there has been a good deal of discussion of the overall structure of the sentence; if you wrote to the point, you might not generate this sort of question as readily.
As for the answer to your question, I will skip considerations of other potential improvements in your syntax, and focus strictly on the question as stated. My answer is, you should add the "for." The second sentence works better; given the verbiage as it stands, I think the second "for" is necessary for clarity. When you read the sentence and come upon the "or" after the comma, you expect what comes next to be an alternative to the last content item in the initial clause ("to think differently"), but it isn't. In other words, without the second "for," the terminal clause appears to be something else you want them to do, thus: "to think differently, or [to do something else]." And that's not the structure you have in mind. The second "for" calls the reader's mind back to the first "for," and away from "to think," and so you get the linkage you want.
