Hello all, didn't take long being here to catch the bug to rebuild an old gasser and I have a few questions. Firstly, I've read here about the lids porcelain coating and see that most shy away from one where the porcelain has worn through, is that more from an aesthetic standpoint or does it affect performance? Secondly, I see that there are differences between the LP and NG manifold orifices, are the burners themselves different between LP and NG? Lastly, I see that some will get a grill to use as a donor for parts needed by another. My question is whether the carts are interchangeable among different lines, for example could a 3 burner Spirit 900 cart be used for a Genesis 1000 or could a Silver B's cart be used for a Genesis 1000? Is there anywhere to find the dimensions(L x W) for the different fire boxes listed? Thanks in advance and any help is greatly appreciated.