I switched from Penske to these because of how noisy the Penskes were (squeaking). Much, much better product. They are soft when you want them to be and stiff under the the right conditions. Just really well done.
Beware. There were a few that had the 3.90 gears with the TT setup. They later went back to stock gears because 1st gear was useless. I have the 3.90 gears as well with the 4L whipple and 1st gear is border line useless. I love the 3.90’s though.