Debbie Halverson recently fired her campaign manager and lost the endorsement of the Chamber of Commerce.
Really...an established incumbent losing the support of the Chamber of Commerce is no small thing. Firing the campaign manager indicates that internal polling by Kinzinger showing him up a bit may have some merit.
I didn't know if you had a ping list for interesting / key House races or not. This is definitely an important one as a chance for a pickup and a younger face to cast off the "old white guy" image of the party.