Personally, if I stirred the topic a little bit here it's for the rocket, not the shuttle. Energija is for me the best launcher; firstly because of the design wich looks pretty cool. The russians have alreaddy been able to anticipate the first things of the reuse with the boosters. Buran is, for me, over priced. Energija have a good story too with all the derivates and has a share oh inheritance with the Zenith launcher and the engines wich are used on actual spacecraft. Like "YourAgony" said, Energija is really powerful and buran is nothing without the rocket.
Your add-on looks just awesome. I hope you will find the motivation for it !
(sorry if my english looks bad, i'm not really good at it :s )