[Disasterpiece]

hm, I found the hook "newreply_form_reviewbit" in newreply.php. This is where the script packs the reviewbits one by one. You could try to get the post id from the last post before the user started his reply, then check for every post in the reviewbit, if it's newer.
Then you can add the css class "isnewpost" for instance to the class list and this way, users could style their templates with an unique and eye-catchy look for the new posts
The css class would just be defined in the additional.css template

I didn't check yet how exactly your plugin works, but I'm sure you'll find a way.