I'll pipe in here. I had the POWERCHIP GOLD 91 software upgrade to my XFIRE. Picked up 17 HP ( 20HP with the POWECHIP GOLD 93 ), went from 26-28mpg (mostly 26mpg ) to 27-29mpg ( mostly 28mpg ) on a ratio of roughly 80%freeway/20% street driving. The horsie increase is definitely noticeable, especiaaly on the freeways when I need to get around bottle-necks. For me it was definitely worthwhile. Their are threads out there concerning UPSOLUTE chip upgrade. Both do the job.