Read a quote from Button i think saying that the new upgrades make the car look sexy ...
That's exactly what they said after the car was first unveiled, earlier in the year and that version of the car turned out to be a lemon. They then made radical changes, effectively using a less advanced version of the car, which turned out to be faster.
Button is extremely bullish about the new upgrades, but until they try them out on the track, they won't have any idea where those upgrades will land them. Also consider that every other team in F1 will also be bringing along some upgrades. I have to say that I am sceptical when a team brings so many new upgrades, all at once. This usually doesn't work out well.
My eyes are actually on Ferrari. I think their methodology of making incremental improvements is the right way to go about things and Ferrari are bringing the 2nd set of upgrades to this race, after introducing a few new parts in the last race (which netted Alonso a solid 3rd place). A lot also depends on Alonso. Right now he is not in top form, but we all know that when he does hit top form, he should be able to outscore every other driver on the track (just as he did last year, in the 2nd half of the season).
I still can't see past RBR absolutely dominating this race, especially if Vettel can lead on lap1.