I managed to get my hatch up to 100 on a unusually empty back highway once, it took forever, about 30 seconds or so. The next 30 mph after 70 is a bitch. I haven't been at that speed or higher since so I'm not sure, but my car was at it's limit, if it can go faster, it can't go much more than 110 I bet.

Also the transmission isn't designed for high speeds, changing the gear ratios can't help cause there arent enough gears in auto or manual, (4 and 5).