Te problem with the P182 side panel is that it has grooves corresponding to the ridges on the inside and this limits the possibilities of merking a smaller window hole withiut compromising the overall look. In my case I removed the inner aluminium sheet which was held in place with double sided tape and some nibs on the edge. The P180/P182 side panels are actually made of plastic (I think ABS) with two aluminium faces. The outer face is brushed and anodised.