I might decide not to change the hammer, as it's a big expense for me and since I'm not doing competition shooting..
While called a "Competition Hammer", it is really a major improvement to any type of shooting you do. As big of an improvement as you saw swapping springs, you will see a bigger improvement when changing the hammer. It eliminates the creep and fixes the hammer geometry so there is no rearward camming when pulling the trigger. It's a big improvement.
Keep in mind that if you DO decide to swap the hammer, you will need to fit the safety leg of the sear to it or install a adjustable sear from CGW.
As far as the guide rod goes, I have shot gun with the factory plastic guide rod and stainless steel guide rod. I've seen no difference in performance between them. In my opinion, you would be much better off putting the money you would spend on a stainless guide rod towards a the hammer.