I found this to be interesting and noteworthy. Trump brought their attack ads up and then passed on these letters from Club for Growth asking him for a million dollars. He turned them down. Now they are one of if not the most agressive agencies going after Trump. A recent article states they are spending 2 Million against him.
Club letters on pdf https://www.donaldjtrump....
Club for Growth Action spends $2 million on anti-Trump ads http://thehill.com/blogs/...