Sorry to hear the slightly bad news, hopefully the engine holds up while you plan the big build as you have certainly put a tremendous effort into yo getting your Zed to this stage!
It goes without saying but the more your tune the Zed then compression issues will show up, the results do point towards worn piston rings and as Greg mentioned you should be able to use it for the last of the summer.
Hope to join you in the 600bhp club!!