I ran some used heads I found off ebay. In my case, it had the rockers and valve covers included, and I only needed valve cover gaskets for them.
That pushrod you listed will work. It had 2 bent pushrods when I swapped heads, and I replaced them all with sealed power RP5000RK pushrods.
I can't really give you a fair comparison in terms of performance gains from the swap because my car was running so crappy before the swap. I purchased my car with a blown headgasket and a couple bent pushrods, so of course I noticed a tremendous increase in performance.
Are you replacing the cam at the same time? If so, what cam did you have in mind?