I decide to fully upgrade my Mini Z F1 cars and ATOMIC is right way to go. Those are perfectly made and fit and finish is superb. If you decide to buy it don't forget that you need springs as kyosho springs isn't best match. You have two spring optins from ATOMIC - AR13 and AR13A. I allso recommend to buy AF7 king pin for F1. Stock king pin isn't smooth so if you decide to stick with stock one you should to polish it. Overall excellent upgrade!