All momo steering wheels require the use of a hub adapter. This is because each wheel is a universal wheel and the correct spline is required to fit different manufacturers. It s also important to set the wheel at the correct distance from the driver and clearance for things like the wiper and turn signal stalks.
Note: this is a solid hub adapter. It is not the collapsible style.
this bracket allows you to bolt on s4 or GTS front calipers to your 1978-1981 928. If you have a 1982-1986 you can retro fit early spindles to take advantage of these brackets.