It would be a good if you'd made significant modifcations that would result in more top end power at the expense of less bottom end. For example, large turbos, high lift cams, enlarged throttle bodies - then the gear ratios available to you would better match the output of the engine.
Effectively, if you made the swap, you'd have a close-ratio box, similar to those found on high output na cars where it's important to maintain high engine speed as you go through the gears. - Think of Honda Vtecs.
If you haven't done anything this significant you're better off staying with the TT diff. It's already matched from the factory to best suit the torque curve of the TT engine.
That's the technical anwser from a performance point of view, from simple driver enjoyment it might be another issue altogether!
Also, consider your driving. If you do lots of high speed stuff then you'd definitely be better of with the TT diff. If you do slower speed stuff with lots of acceleration then maybe go for the NA one.
As a final point, I think it'd be fair to say that switching diffs will hurt your fuel economeny, too.