The real problem with wheel arch moulds is one of proper fit - or lack thereof. For some reason, well it's really poor design, the moulds do not fit well in certain areas of the body - and the cut-outs on the moulds are always in slightly the wrong area.
Gleaming Beauty at various times (my 6.9) was fitted with moulds, but deterioration of old ones, fitting of new, meant there were just so many fitting holes in the guards, and the whole concept started to look ugly (well, with what I COULD SEE AND KNEW IT WAS THERE so that, in the end, I fitted 'virgin' replacement guards free of holes. Additionally, when attaching the sides of the AMG reproduction spoiler to the front guards, there is preciously little space to also fit the moulds - the edges of the front bar are also inclined to interfere with the proper fitting process. Regards Styria