anyone have experience or heard much about the g-techs? how accurate are they? are they worth the $$$?

I was thinking of getting the pro-rr but i would also like mine fixed. 
I got the nicer one for Christmas a few years back. Never really used it, just played around with it a few times. I know you gotta have the weight right on down to the pound or the readings will be way off. A lot of people put in what they think it weighs, or what it says on the door, but that doesn't work. You have to actually weigh the car with you in it and have it exact. If you have a passenger you have to add that. I do like the shift light on it haha. I might take it to the track with me next year and see how accurate it is. I'd much rather be able to make passes on the highway in my home town than drive 2 hours to the track.