am I right in thinking that if you add a spacer or adapter to a wheel you, in effect lower the ET? For example if a wheel has an offset of ET55, by adding a 20mm adapter you end up with ET35? and if you have and offset of 23.3, by adding a 20mm adapter you get ET3.3? If that is the case is it possible to roll and stretch a wheel arch 32mm with an arch roller tool?