2 cents.
just want to make a note, it is important to preserve original text
(yes i am talking about formatting, spacing, tabs etc)..
because without it i can easily imagine you can raise compression ration to the skies..
but as to me the original text is important part of game.
Don't worry, formatting information will be stored in Bonsai (as extrinsic information of the flyweight like node properties, not in the flyweights themselves).
You won't notice that there is no original text, source will be reconstructed on demand.