Would muslims be offended if I write/ highlight verses in the Quran that split in Eng

I mean personal notes, cross references etc.

why should they

I've done it, DONT TELL THEM, they freak out. Man I thought the guy was gonna strap himself with a bomb and run at me. LOL

No, knowledge seeking and study is a part of the Muslim religion.
Infact some Muslims do it. Moreover, translators put foot notes
sometimes too. But when I'm studying stuff I always do it on separate paper so the primary material won't become a cheat sheet if you know what I mean.

How the hell would they know what you write. If you have to highlight, then by all means do so.

Its nice of you to ask....we really don't need to offend any group of people. What is the point.

I would suggest to try and write notes on a "stick on" kind of thing. I would personally not do this out of my respect to the Quran, as a Muslim. Besides this if you have questions about our religion, feel free to email me at haseeb_khwaja3738@yahoo.com, I see there are two other Muslims who answered your question (at least), I am sure anyone would not mind to help you understand our religion better, peace. BTW your question was polite and not offensive!

No, it's not offensive, but I personally try not to mark any book if I can help it. Of course, for studying, it's different

Try to write on the English side so long as you don't write something offensive, i don't see anything wrong with that.

I commend you for going through that much to learn the Qumran.