Get the SS flavor bars from RCPlanebuyer on Ebay. If you want, I can give you his direct contact info. His bars are ss, thicker gauge than Weber OEM and cost less.
For grates, it comes down to cash flow versus value. Teh absolute best value long term is to invest the money up front for stainless rod grates. You will never have to replace them again. RC makes a set of them for much less than they would cost from Weber.
As for other non oem rod grates, can you post a link to which ones you are looking at ?