came across this (there is hope for you yet):

Quote Originally Posted by vine@trifecta
Yes - the transmission tune from the factory is terrible. In fact, by the time I bought my car, GM had already released an updated transmission tune (including a new operating system).

The Cruze uses a brand new transmission controller (called the T76) which is very similar to the T43 used in the existing 6sp automatics.

The Cruze does NOT come with a SPORT mode from the factory, but I added one to mine through the TCM tune. When the shifter is in D mode, it's one profile, and when I move it to the manual quadrant, it goes into an automatic-shifting "SPORT" mode, and then you can TAP it from there. When we get to select-a-tune working for the Cruze, I will probably tie it to this on the automatic cars.

The Cruze appears to have an LSD from the factory. When I floor it (with our tune on it), both tires spin. LOL.

The Cruze uses the same transmission as the 180HP Buick Regal 2.4L SIDI, so even with our cranked-up tune, we're well within the designed torque specifications.

As for tuning it goes, I've tightened up the shifts in SPORT mode, it made a BIG difference. The factory desired shift times are around .5 seconds. I pulled this down to .1 second and it shifts immediately. I need to work on downshifts yet, but initial results are very encouraging - better than what I was able to achieve with my Buick LaCrosse.

The 6sp automatics have a very sophisticated torque management system. It is possible to greatly exceed the design specs for torque input as long as you don't try to carry the torque through the shift. I've tuned 6sp automatic Corvettes making over 600HP at the input shaft of the transmission that live a long life yet because the TCM is so effective and getting the ECM to remove torque during shifts.

So, in short, with careful tuning, I believe the slushbox will be able to handle lots of power, and we might even be able to turn it into more of a gearbox. Haha!
since the cruze is essentially a daewoo just like the aveo, you might be able to get vince to tune the transmission for you to get better numbers.. mpg or otherwise.