The new G-tech is an awesome tuning tool. One of the best things i have bought for my cars. So you say it is off by as much as 10%? if you took your car to ten different dynos you would get ten different readings, And I'll bet my last dollar the varience would be more than 10% between dynoes.

I tested it on three different cars.
Yellow car. Dynoed in 2wd mode at ss showed 400whp. gtech dyno on the street with wind resistance and 4wd, 370 whp.

Nicks FWD talon. dynoed at glens, 190whp, 210tq.
gtech a few days later 190whp, 220 tq.

Brittans 20g car. gtech 350whp. track 12.1 @116 in 3125lb car.

i'd say anyone who has bad things to say about the new g-tech prolly has never used one and is just repeating what other dumbfucks posted on another board.

its a tuning tool with plenty of places to make tuning errors. in the hands of an idiot dont expect much