Is it actually "creaking", or making a dying whale type of groan on tight turns..? The groaning from the rear end is normal for the carbon fiber diff clutches... They all do it. Temporary fix is to do some gentle figure 8s. When you get on it hard again though, the diff clutches are jammed together, and it'll make the groan.
'08 Bullitt -Highland Green
'09 GT-500KR -Black/Black