I'm reading Low & Slow by Gary Wiviott so I can learn how to use my new WSM. He tells readers to use a second charcoal grate setting on the original grate at an angle and to use lump charcoal. I called Weber to get the charcoal grate after trying to find one locally. Weber refused to sell me one and told me that setting a second charcoal grate on the original charcoal grate is considered a modification to my WSM and will void my warranty. They also told me I can't use lump charcoal in my WSM and that I should only use hardwood charcoal. Lump charcoal IS hardwood charcoal. I asked them why I can't use pure, hardwood lump charcoal and must use charcoal briquettes made from wood and several other non-wood ingredients. The person on the phone didn't know the reasoning except that lump charcoal burns hotter. I then asked why the WSM can't hold up to using pure charcoal. It sounded like they consider using lump charcoal an abuse of the WSM. I think you get my drift. This was a very, very weird discussion that included input from a Weber supervisor. Anyway, they refused to sell me the charcoal grate for my new WSM.