According to the rules 4 or more alterations equals one modification. A conservative custom has 0-3 mods, mild has 4-6 mods, semi 7-10 mods, full is over 10 and radical is any number and alt least one of whis is chopping, channeling or sectioning. If they really looked at my car there are about 50 alterations so I likely fit in the semi class. The class covers 1949 and newer convertibles.