Why do you need an echo to do 140?
There isn't much you can do to improve the handling of the Turbo Vitz. I've logged almost 90% of my free time on GT4 on FF cars, and among them, the Vitz is a dog. It suffers from terminal understeer, and has such a short wheelbase that tuning it out is just about impossible (just like with an SRT4.).
Best you can do is mix tire compounds to try to get the rear to unstick a little. Also, try shifting the weight forward by making the front about 10mm or more lower than the rears. And unless you're on race tires, tuning it to over 200hp will just about ensure that it will be undriveable.