I bought into X wing some years ago, but never really got around to playing (I have all the ships through wave 3.) I'm planning on getting some friends to play, and was going to do a demo game, pitting Luke vs Vader (with a couple other ships.) Having seen though that the Tie Advanced was given a Title to correct an imbalance, should I proxy this card? (ie, is the assumption that the Tie Adv is properly balanced only if it uses the card, and thus the game with be better if I use it, or was it to improve it vs later waves, and its actually balanced against X and Y wings (and thus using it seriously overpowers it?)

I'd say that the TIE Advanced Title card was introduced to help the ship handle the meta at the time of its creation. If you're only playing within the first 3 waves, then adding the title might unbalance things in favor of Vader & company... of course, so would adding almost anything from a later wave, into an otherwise restricted meta. Of course, that restricted meta would also be affected by any current rulings and FAQs, as Wave 3 Biggs had a lot more prominence than Wave 13 Biggs currently does. So, you may want to avoid modern FAQs as well, to preserve the early-wave game experience (and not unbalance everything).

That said, I think a nice basic squad of classic ships (Luke + 2 X-Wings versus Vader + 4 TIE Fighters, or so) would make for an excellent demonstration game. In fact, one demo method I prefer is setting up a number of Rebel pilots as single ships in the 30-35 point range, then scaling up an Imperial force for myself to run against them. With one skilled opponent versus 3-4 rookies, you can demonstrate game rules through intentional sloppy play (like showing a barrel roll, but making it cause your next ship to bump and lose its action) and help teach players while giving them a fighting chance at a win.

Ah thanks! Does that same logic work up through wave 5 do you think? If we run heroes of the atari cluster I'd like to keep the ships geared the same. I've no issue in printing cards to proxy so y wings could get TLTS for ex.