I still think it was highly implausible all of the clones instantly turned on the Jedi in the first place. It's not like they were subliminally programmed or anything, there's still a chain of command and I'm pretty sure "Lord of the Sith" does not outrank "General of the Republic Armies".
And are we really to believe ALL these clones were trained to understand and execute this order ahead of time and NONE of the Jedi got wind of it? Suuuuure.
First of all, a "Lord of the Sith" wasn't the person the GAR was responding to: it was actually to "Chancellor of the Republic", which is essentially the same thing as the US President being the Commander-in-Chief of the US military forces. Going one step further, the background material for ROTS (BTS books and especially the novelization) stated that, at the beginning of the film, the Senate enacted a law (put forth by Palpatine surrogates) that gave the Chancellor direct, top-level command of the GAR *and* the Jedi Order (this explanation would have preceded his conversation appointing Anakin to the Jedi Council as her personal representative). So, Order 66 was not given in Palpatine's capacity of Darth Sidious, but in his capacity as CIC of the GAR via a secured comm channel, and thus, regarded as a valid military order from the supreme commander of the military forces.
The Karen Traviss "Republic Commando" books (which are excellent reads, btw, and IMHO, one of the best things that the EU has given us) start each chapter with a background quote of some piece of the story that might not otherwise fit the narrative structure but is still important to understanding some of the motivations. In one book (which might actually be "Order 66" although I can't recall) some of the GAR command code is listed; Order 66 was a contingency in the event of treason by the Jedi Order, with similar "Orders" in place for treason by other government entities, including the Chancellor himself. This was apparently instilled in the clones from birth by the Kaminoans and the training process. It's also stated in the ROTS novelization that the reason the Jedi didn't anticipate being murdered is because the clones did it without emotion or thought, implying that, to them, Order 66 was just another order that they were following.
All this being said, I've always preferred that Order 66 was a subconscious implant that Palpatine/Sidious triggered when the time was right, mostly due to the whole "independent thought" aspect of the clones that we've kind of seen a bit in the animated series, but also in the RC book series. Kind of a "sleeper cell activation code" as it were, but LFL's kind of poo-pooed that theory by stating it was just an order and the clones were "just following orders" as it were.
Back to the Y-Wing, I've been pretty happy with it as the weeks have passed and I've gotten used to it not as a new toy, but as a toy overall. My only complaints are with the non-turning turret (it really couldn't have been that hard to make it rotate) and the rather superfluous label sheet. Well, and the price, which is still about 25% more expensive than it realistically should have been. Those things aside, though, I do think it's a great and well-designed toy.