Full disclosure, my father in law bought these for my wife's car. He is an autocross person and we ended up using just two of them that came in the box. That being said, I know very little about this product. They have been sitting in my garage for close to two years now and I am looking to find them a new home.
Please message me if you have any questions, and hope this is a good deal for someone. I know they are pretty expensive to have shipped over from Europe.