You may find that the sulphurous odor is generated by a bacteria in the water supply. Changing parts in your water heater isn't going to solve the root issue. The sulphur producing bacterial are not a danger to health but can make for an unpleasant experience, especially at this time of year. Once they get into the hot water system, it's difficult to deal with, but it can be done. We have a chlorine injection system on our well to help deal with it at the source and the chlorine is then removed by a charcoal filtration stage when the water enters the house. When we moved in here, the water conditioning firm that put the system in for the previous owners came out and over a series of visits, we added some chlorine "internally" and then ran ALL the faucets and fixtures for a bit to get that solution out to "all the places", which included outdoor faucets, etc., as well as getting some into the water heater. It took several iterations of this to knock things down and we now only have limited hints of the odor, primarily in the spring. The injection system helps keep it down before the water enters the house. (The previous owners apparently "forgot" to get chlorine into the bin with enough frequency to maintain the injection treatment properly, so our first year year was "interesting")