I would not recommend Cornerstone of Plymouth. I purchased a year old used vehicle with 15K miles from them in late fall of 2018. The sales person was very nice, and included the history of the vehicle - which included information that the first owner drove this in Canada for the first 7500 miles, and the second owner (the sales person) drove the vehicle for the second 7500 miles. He also explained that the vehicle was picked up at auction (by Cornerstone I assume) specifically for the salesman as he was looking for this specific vehicle. I appreciated his candor on the history of the vehicle, and he stated that Cornerstone takes pride in their transparency and honesty at the dealership.
I decided to purchase the vehicle (it was listed at a VERY fair price, I
'll give Cornerstone high marks for their fair pricing), but when I told them I would be writing a check for the vehicle, it seemed like a few things changed. I specifically made it known I wasn't interested in financing as I'D BE WRITING A CHECK, yet I had to wait for and meet one of the sales/finance managers (or someone - I was annoyed so I didn't pay attention) who took up 30 minutes of my time attempting to talk me into financing, including suggesting to me that I finance through Cornerstone, AND THEN I could write the check to pay that loan off. I was really troubled by this. I've done enough car deals in my day to understand the financing is as big of a business for auto dealers as is actually selling vehicles for profit, but I stated I wasn't interested in financing, and it didn't matter - they still assumed they could talk me in to it.
Fast forward to the next day when I brought the check in for the vehicle, and I had to wait almost an hour to see the F&I person (the person you sign all the paperwork with), even though I made an appointment for a specific time with the sales person the day before. I then take delivery of the vehicle from the sales person, and I was handed one set of keys and a fob. I asked about the second set, and was told something to the effect that since this was an import from Canada bought at auction, there wouldn't have been a second set (really? Canada only sells cars WITH ONE SET OF KEYS???). The salesman did tell me he would give me the number of the locksmith that they use to get me another set. The vehicle had not been detailed, as the interior hadn't been vacuumed and the inside of the windows were filthy (in the sunlight, so maybe they did a poor job of wiping them and didn't know). The tell was the white film on the bottom of a door or two that was there at the test drive that the sales person said would come off in final detail - but was there when I took the vehicle, so OBVIOUSLY no final detail was done. Additionally, it wasn't until the next day after delivery that I realized a headrest was missing in the backs seat, which Cornerstone did offer to order for me, and they did.
I called the locksmith whom the salesman recommended because they do a great job at a fair price, and drove up to the 610/Zane area to have my key and fob made, and the locksmith didn't have either correct (GM branded) pert on his truck, so he'd give me 'what will work'. A fob was programmed (that works) and a key was cut and programmed, that happened to work 30 seconds after they handed it to me - but didn't work as soon as I got home and tried it again. I called the locksmith immediately and was told to drive back up there and they would give me twenty bucks back of the 120 I paid them. They gave me forty bucks back (gee thanks) because the key didn't work, but the multiple hours this process took, and the fact I had to go to them was annoying. I did not let Cornerstone this was the end result with the key thing, as I had really had enough of them by this point - and had zero confidence that they cared to take care of the key issue for me, to make me a happy customer that would recommend them.
So much for transparency, honesty, and customer happiness.