hey in my Mustang 5.0 and Fast Fords
there is a ad in there by Mrbodykit.com
they have cobra r's in 4 lug with 4 bolt patter
http://www.mrbodykit.com/wheels/1979_1993.htm
but on there Cobra R's it has a R in the middle and on American Muscle they have a M in the middle, why is that?