There doesn't seem to be any way to get notifications for suggestions that I haven't voted on.

But for my team's ZenRep, I will often ask clarification questions on other peoples' suggestions. I want to remain neutral on the suggestion itself (don't add to its Supporters / vote count), but still get email updates when the person replies to my comment.

It does not seem like this is possible currently. I would like to see a separate Subscribe / Follow toggle button. (Which is automatically selected if I do upvote something).