Couple of buddies of mine and I went in on a G-Tech a few years back. Works good, seems pretty acurate. Above all, it is nice to use to see improvements made on money you spend. One example would be a 0-60 time of 6.3, but doing nothing but putting on new struts, lowering a tad and getting it alinged yielded a 0-60 of 6.0 every time. So neat just to see how things like "Squat" really affect lost time on take offs or even shifts.
Get one, they are cool to mess around with. Turn it sideways and you can even messure your lateral G's!