1-The ID of that widget area is sitewide-top-widget-area so the rule would be
#sitewide-top-widget-area widget-title {border:none;}
2- You cant because if the item on the menu is smaller than the Sub menu, the sub menu would be cutoff. What you can do is make all Sub menus the same width with
.menu-primary .wvrx-menu ul li a {width:100px;}