Change how quoted text appears?

I’m sorry if this has already been covered, but I couldn’t find anything.

Is there a way to edit how a quoted email appears when replying? I’d like to replace the “— Quoted Message —” with a line, and change the To, From, Subject, etc. labels to bold. I would also like to get rid of the vertical line to the left of the quoted message body. (In other words, I want it to look like the replies in Outlook).

Unfortunately, it is not possible at the moment.