You might want to take a look at this font, it's the first one that comes to my mind: http://www.dafont.com/linkinpark-chase.font
But if you really like a font, and you just need an R like this, I'd say it's easier for you to just modify it in Illustrator rather than spend hours looking for something you might not find.
It would probably be easier for you to just modify one letter (in Illustrator for example) especially if it's just for a title (but I'm assuming you need this only for a title).
You can only be sure if you ask the author of the font you want to use. Every author might have a different answer to that question.
There is no general answer to this question. You need to contact the author of the font you will choose.
You are not using a better image, but the same image. This is why you can't post it again.
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