No, a proper tune is done using realtime air/fuel metering during a run or dyno pull and then adjusted to maximize power, performance, driveablility, etc, AND maintain a good and safe a/f ratio throughout the power curve during full and part-throttle. Messing with that unless you change the setup will be counter productive. Most base chips/tuners, etc just lean out the a/f a bit, change the fan on/off temps, and bump up the timing... they are generic and best for stock or near-stock setups, the more mods the bigger benfits of a tune. For example, if you put on a supercharger you'd be suicidal not to get a custom tune.