I am rather thankful that all mine needed was some glue to the connectors, a lick of paint and decoration and my lid milling out. I bought some 12mm Nylon 6, and found out its [i]too[i] light. I was trying to take 500g off the robot; the steel lid was 2.225kg, the nylon 6 one was 553g :P. That puts me roughly 1.6kg UNDERWEIGHT, but I wanted to be up to the limit, and I found out that, despite me asking for my lid to be 6mm steel, my fabricators made it 8mm. So its currently getting 2mm milled out of most of it to take 500g out of it and bring me back up to near the limit.