If you're looking for boxers in NJ. I would look into Avalon Boxers - http://www.avalonkennels.net/
. They are supposively reputable. I contacted them twice and they never got back to me. But maybe you'll have better luck. I've heard good things about them. Also try Pheasant Hollow Boxers out of Walkill, NY.http://www.pheasanthollowboxers.com/
It's like 10 min from NJ. I went to visit Kerry Jones there in April and she was great. The dogs were beautiful, especially Louie. He was as solid as can be and a great looking dog. Pheasant Hollow has a couple female's about to whelp in July and August. Good luck.