I compared my wheel to your SF Challenge ( I have the Ro-Ja R2-5 which is exactly the Volk 57F Pro) and the lug seats look exactly the same...which means you need tuner lugs.My guess is its a Rays Engineering standard.
*****
src="http://www.photodump.org/stored17/IMG_01362.jpg">mg src="http://www.photodump.org/stored20/46.jpg"> |