(a) See permitted modifications listed under M6.4.1 and
restriction stated in M6.4.2 In relation to listed cars, any
further modifications will cause the vehicle to be reclassified
into class 8.
(b) M6.7.1 - The use of wheels of diameter(s) other than as
specified above will cause the vehicle to be reclassified into
class 8.
(c) M6.8.1 & M6.8.3 The use of gearbox and rear axle
casings other than as specified above will cause the vehicle to
be reclassified into class 8.