There is nothing confusing...
The '4' is the latest flagship marker from WDP. It supersedes the IR3. There is no other marker being manufactured for sale at present with greater specs etc The only other one they are still producing in large numbers is the Speed (same basic engine, less fancy bits)
Dynasty are having a signature/special version of the '4' and Dynasty themselves have said this. There is more detailed info on this over at
www.angel-owners.com although no 100% accurate details of the Dynasty edition have been released. I would be suprised if the Dynasty 4 doesn't make an appearance at world cup.
Ultimately it is unlikley to offer anything performance wise over the 'stock' 4 as it has always been the policy of WDP to produce the best possible marker meaning no additional upgrades for the buyer... However, it is sure to have some fancy cuts and paintwork