MOST stuff that is sent to me especially the new Pro-form/QF stuff is pretty nice and the tunes are just a bit off but every carb has to be tuned into the combo and it's going to be based on several factors. Altitude, weight, fuel, compression, gear, vert etc. and some are installed and set new bests and a few have me scratching my head but all start w/a baseline tune to make YOUR job easier and hopefully new best et's or mileage or whatever better..........