Widget with no border and scroll

Hi, could you look at http://bettingtip.info/ Recent Comments widget its Recent Disqus comments widget.
Can you help me to add this comments in scroll box, i mean to show 40 comments but in scroll box. also its possible to hide border of only that widget and some css for text (title and comment) background, odd /even rows padding..

similar theme was here maybe that can be solved on similar way https://premium.wpmudev.org/forums/topic/css-remove-border-for-only-one-widget-not-all