It would be good to know if anyone has directly compared the quality of Trim Parts to ACC.
I have. I installed an ACC carpet in one of my Roadrunners a number of years ago. I found that the carpet fit nicely, but they didn't give me a lot of extra material on the sides to work with. The carpet also faded badly in a couple years. I wasn't very happy. Since then I've never heard anyone complain about having enough material.
The carpet in my 300 was an ACC carpet that a PO had installed. I really didn't think it fit very well, but I put some of that off to a sloppy installation. The biggest problem was the carpet was extremely faded. The guy I bought the car from from had said the same. It had been done just before he bought the car and the carpet had faded soon after.
I decided to try the Trim Parts carpet. I spoke to the phone rep about the fading issue and he said I would be happy with their carpet. He also cut me a little better deal, possibly because I said I had bought ACC carpet in the past. I also bought their mats, which were a piece of carpet that was the same carpet only backed backed and edged.
The carpet fit very well. I was happy with that. Lots of material to overlap the edges and front and back. Two years of driving around with the top down, I haven't seen any fading. I'm very happy with that.
That isn't saying that the ACC carpet is junk. For all I know, they may be using the same materials and the newer stuff has a better UV treating. I have a roll of ACC carpet for my Windsor project and I won't hesitate to use it.
IMHO, the Trim Parts carpet was very good. In my experiences, I liked it better than the ACC, but it's always a "Your mileage may vary" type of thing and ten people will now say "My ACC carpet was great!"... So there's that. But if the Trim Parts carpet is $150 less... That's a "no brainer".