Well, since you asked about Concord Acura- here it goes.
I bought an Integra from them (1992?) and found service to be fine - they even installed a DC Sports suspension on the car for me.
Then in May 2000 I bought a 2001 CL Type S (Burlingame Acura since Concord was quoting me $2,500 over MSRP to get the car - this knowing I had paid cash for my last Acura which they sold me) and took it to Concord for service when it had 5K miles on it, August 2000.
While at Concord Acura the back bumper was damaged and the damage was not disclosed when I picked the car up. Fortunately for me I checked the car before I took it off their lot and discovered the damage. I pointed it out to their service manager; my writer was already gone for the day. He told me they could not have done it. The next day, the actual service writer that took my car in confirmed it was flawless and dentless when dropped off. (I always walk them around the car to make sure there are no issues re dings, scratches, etc. Twice I have had a car damaged while in for service.) They agreed to have the damage fixed. I cautioned them strongly about doing some fly-by-night quickie and they assurred me it would be just like new. OK, to cut this short, after 3 attempts to repair the damage and failing, they took a new bumper off a new car and put it on my car.
Fast forward to my '01 NSX-T, bought in June 2004. I wanted to take it in for a 30K service even though it only had 11K miles on it. Basically I wanted a baseline on the car to make sure everything was as it should be since the car came from out of state and I never met the prior owner.
I called Concord in advance of the car arriving and inquired about their price for a 30K service on my car -specifically making sure they knew it was an NSX and not an RSX. English was the issue that caused me to make sure we were reading from the same page of the same book. They gave me a price.
I then called Pleasanton Acura and got a price from them for the same service. By the time I got off the telephone with Pleasanton, Concord called me back and said they had made a mistake on their price and needed to raise it by almost 50%. I told them that was interesting because Pleasanton had quoted me almost the identical price they had initially quoted me. Then the service mamager came on the line and told me they would stick by their initial quote, since they had given it to me already, in light of the fact I was an established customer. I said OK and scheduled the 30K with Concord for July 6th, 2004.
The next call I got, later that same day, was from their servicer manager advising they could not meet the price they had quoted and that was that. They claimed the difference was that the valve job was 6 hours all by itself and they would lose money. I said that a valve job was a part of the 30K service as indicated by the book and the service manager said, well that may be but it is really optional. Besides with only 10K on your car it is not going to need one. I told him the point was I wanted all the valves checked because I was just buying the car and wanted to make sure all was correct. He said he would not do the service for the price quoted. I told him Pleasanton had said they would and that if he could not match the price, sticking with their initial price, I would not return to their dealership again. I then followed that up with a letter to the owner of Concord Acura and never heard a single word from them.
I took my car to Pleasanton Acura and they did the service and the only issue I had was they spilled coolant during their service work under the hood and did not wash it off. Strong smell forced me to return so they could wash it out. Very nice people and took excellent care of my car otherwise. Two other NSX's in for service at the same time mine was there - made me feel good.
So - as far as I am concerned, Concord Acura is not on the map. That is my 2 cents worth for anyone who is interested. I do know that Concord Acura went through a few service managers during that time period, but to be frank, when the owner or his designee did not get back to me after I took the time to write, that was the end of them for me.
Good luck.