It does look like you've been following the missions for quite a while!
As far as the "tweaking" of the design, I should be able to enter the name of the different shuttles in a search engine/ image search and see the changes you are refering to. The Endeavor should be a bit smaller, if you say it is lighter, or they just found ways to cut weight inside the craft.
That is an interesting story about Congress and the agency. It makes you wonder "which is the dog and which one is the tail", so to speak.
On the Buran, I guess I never paid close enough attention to know that Russia had a very similar craft to ours. If we didn't know better, the very close similarity would indicate that there is a lot of technical co-operation going on, even during the "cold war".
You were not provided the best picture to make your assessment with. I'm sure you would have picked up on the details if the pic was better. Yes, the link you provided shows the very same picture sent via sstv.
Thanks for adding some interesting details to this topic.