The 501 VT-Spec Wheel was originally developed for the Factory Subaru Rally Team. Think of it as the 15 in. version of the Rally wheel version. Another key difference is the stainless steel lug hold inserts for increased durability in race environments. Unlike the Rally wheels, the VT-Spec will not clear OEM Subaru STI brakes, but will clear Subaru WRX 4-pot brakes up to 2014, AP Racing CP6720 calipers and most brake packages with rotors up to 300mm in diameter.