Well the ISOs don't match, and I am also trying to figure how the WZT doesn't need a key. I downloaded vs_ultimate.exe from MS (The 90 Day Trial), and am running it with /layout to download all contents. I am going to compare all files. I am still waiting on the download, but I confirm the vs_ultimate.exe (one is in the download/ISO and this runs setup) between WZT and 90 Day Trial are different. I will keep you updated and try and pin down the differences.