Not sure how you got them as the ones I have were made years ago by a fabricator friend of my dad's. I have never seen them anywhere else but with mine, my dad's and now th eone I gave son in law. Anyway as for "improvement" it's hard to say. I have switched back and forth from double to single row. I think the single row cooks a tad more evenly. I actually got the idea from a Weber rep. I called with an issue on my original Genesis 2 being uneven. Rep said try taking out the top row. Well it helped so I commandeered my dad into asking his friend could he make a set like the newer grills had but to fit the old. I gave him specs and he built them. We're all still using them