Ok if ya aint going to mod it an you want the one thats faster from the factory you should probably go the gtz - problem with this is finding one that isn't stuffed. Mind you same peoblem with the starlet! Take them for a drive decide what ones quicker then take them for a drive down the same piece or road and from the same point at the same speed nail both and take speed at another point slightly further down the road and compare!
If you are planning on moding the hell out of both cars you will get roughly the same result out of both - a high powered front driver that you can't really use the power from because putitng your foot down = masive wheelspin if your after max power the gtz wil lwin out at the end of the day because same money spent = slightly more on the gtz cos of the simple fast cubes rule
Then there's insurance - make sure you can get i tbefore you but one!!
But at the end of the day you have to remember only one thing - we aint driving whatever you get so it's up to you what you like the most!