Just picked up the GT-1 version of Escort's performance timer:

http://www.escortradar.com/gtimer.htm

It's kind of a toy, but it's fun to play with. Shows G-forces (forward, reverse, and left/right cornering), 0-60 times, 1/4 mile times, and horsepower employed during any given "run". The best part is that you don't have to wire anything -- just stick it on the windshield, plug it into the cigarette lighter socket, and go. Not sure how accurate it is, but I manged 7.3 seconds and 7.1 seconds with two 0-60 runs, and that was without sidestepping the clutch. So it seems to be reasonably accurate, at least. I don't use it as a serious measuring tool, but more just to get an idea of how the car is performing.

Best,
Bill