I feel guilty, but I did it. I bought off brand cast iron grates from Amazon for my EX4. Spec'd for Spirit 300, same as the parts that Weber now show as compatible with the SmokeFire. Thought I would share some pics and later follow up on how they perform\last. The are solid cast iron and the measurements 17.25" x 23.5" when side by side. They fit same as the stock grates with more slope than desired. Probably 3/4" gap if they are pushed apart. The short way, they fit with no issue. The obvious up side going this route over Weber is cost. These were $26.99 for the pair shipped. At one point I had a set in my cart that were only $20.89. I debated too long and the price went up, so I grabbed these. There are several brands out there, probably all made at the same China factory. This brand is Stanbroil. Here are some pics.