Well I think this is the first time I have to disagree (slightly) with Scubatech.
To your original question, HCP or Northridge CO. Both are good shops. I have done business with both, although I am exclusively a Northridge customer now. The reason is simple - the manager of the CO location, Oliver. Oliver is as straight up, honest, helpful of a Jeep guy you will find. He understands that this business is all about building a long term relationship. Both shops are competent and will do a good job of building your jeep. But 2 years from now when you have an issue, that is where you will see a difference, IMO. Oliver is not about making a sale, he is about building customers for the long term. If you have an issue 2 years from now, Oliver is going to work with you to help get it fixed. That is just the kind of guy he is. He delivers an outstanding customer experience. I can send him a question in an email on a Sunday and he responds in 15 minutes. A year or two ago I had an issue with something I purchased there. At first I got some push back from someone at Northridge up in the Washington location. Oliver jumped in and made it right. That is the kind of service he provides - I don't even remember the problem, all I remember is Oliver making it right.
And just so you know, I am not a personal friend of Oliver or anything like that. I am just a customer like anyone else. Oliver gets it. He knows its not about one sale, its about the long term.