Here's my stab at a tweening extension for Go.
It seems to be working as fast as it can with OverlapMonitor
http://blog.hydrotik.com/2007/12/20/as3-tweening-go-hydrotween-rev-031/
HydroTween.go(target, {width:760}, .8, 0, Exponential.easeInOut,
onCompleteHandler);
Thanks Mo!