well, u can do a reguler thing, that is resize and balance the featured artical width to match the whole theme width. or you can leave it like this. and make it as a unique style ( I mean break the design rules ) use any background color until your featured content section. and from end of that featured content line border put another color ( use gradiant type looong hight 1 pixel image for this. then your blog will has a unique style. its useful Good Luck Bro
//or I increase my regular blog content to be the same size as the 2 featured?// Thats also a good idea. becoz its not gud to reduce your featured content width.