You wont save much on aftermarket. Get a genuine Weber starter.
I got a genuine weber that was made for genesis silver, gold, or platinum. It actually was 2 dollars cheaper than the replacement starter at Home Depot. The push button mechanism didnt fit on my grill so i just used my old one and just used the new wires from the replacement set up. I had the little box pointed the wrong direction (up instead of to the left) so it took me a lot longer than it needed to. I also was trying to do it in the dark with a cell phone flashlight. I finally hooked up a shop light which expedited things nicely. Tomorrow i am going to clean it up to see what she looks like.