I called them on an issue about two months ago.  Got a call back and a response to the email I sent within about a week.  I was getting read for a vacation so I could not take full advantage of the conversation. When I got back six weeks later I called and sent them an email with a question.  Two days later I receive a call and a response to my email.  They spent some time with me gibing me information and I was impressed.  

I have now sent my TBI's in to get bushings and cleaning they said expect a few weeks (actually they said at least 3 weeks).  Which is longer than I would have liked but realistically would be about twice time it would take to find someone locally and get it done.  But I would have to worry about if they knew what they were really doing.  So the extra time is worth it.

A tip, DCS gets a lot of phone calls during the day and typically do not answer as if they did they would not get a lot of work done.  So make one call leave a clear message and they will get back with you.  At least that is how it worked for me.  Better yet send them an email and give them a call.  That way they have two means to contact you.  This method as worked perfectly for me.  

I have purchase a number of things from them and all have been delivered in a satisfactory time and condition.  Have not done their Crossfire manifold yet.  It may in the future I'm just not sure I want to take that next step.

Just wanted to let people know that own Crossfire cars that I have had good luck with them.  

PS they recommend starting at 12.5 to 13 psi for fuel pressure.  A 84-85 corvette fuel pump will make a world of difference in your cars performance.  That fuel pump when the pressure is adjusted correctly work great.