At least it wasn't as bad as turkey. I thought it worked quite well there, created a lot of tussling for position under braking, but quite a few clean passes where the driver without DRS was just defenceless.
Back on topic... a 2-3 km/h advantage over 1.2 km is a lot. The straight is also fed by a corner with a very high speed exit, so you can almost immediately be on the limiter. I believe you spend something like 1/5th of the lap (time wise) on that back straight.
Given Brawn's recent comments, I'm not so sure they lack downforce... and in any case it would only hurt them a lot in 2 or 3 corners. Victory will not come if they can't get the tyres working for them... and of course, access to DRS and the double boost their duct gives them is not something they are guaranteed.
I wouldn't hold my breath for a maiden victory. But pole? I think they definitely have a very good shot at pole, and I mean a better one than they did in the last 2 races. Especially since Mclaren don't seem to have the top speed advantage they used to, though they have been quite successful at shanghai in recent years.