the dyno will make the whole package work as a unit. gears, tires, case, trans and motor. the mail order tunes are a good "base" that is designed to make many customers smile with the same product. both are good and have their place. as far as andy is concerned i think mail order will be fine, but when more tweaks are added to the motor and you want to pull every last drop out of the motor.....a one off tune with a dyno helping you will be the best.
thats the opinion of the not so all knowing grassman