It actually all fit if you have the aluminum arm mounts. You cant adjust wheelbase any longer because the TC7 arms are wider. I have about millimeter of play on front so I will shim the front arms back. Currently its about 3 mm longer the my 7.1 but I may mill a millimeter off the arms to move them forward. Waiting on shocks and then testing can begin. I tried to use the TC3 rack but it didnt have enough throw to go full lock. The TC4 is narrower then the TC7 so I will probably add a 1 millimeter to each side to get it closer. The arms are almost the same length. The other issue is axle pins are a little smaller. Probably wont be an issue but if it is, 2 solutions. First one is to sleeve the pin with some brass tube. The other is to mill the outdrives so I can use the AE blades on it. Also could press the pins out drill the axle and press tc4 pins in. The other issue is sway bar end links are different but TC7 ends will work. I have them on order also. This is gonna be my USGT car, my fun class as I call it since I also run 17.5 sedan.