there are preset tunes on there already for mileage - the MPG Booster tune... and for a preset performance tune, you have the 87 octane tune or the Diablo Tune - which is made for 91+ octane...
there are no downloadable custom tunes.. tunes are tied to a vehicle's VIN number and engine calibration ID's and therefore can not be shared...
you'd need to purchase/get custom tuning done specifically for YOUR vehicle and how your vehicle is running, what it needs for fueling/timing adjustments, etc... which I can certainly hook you up with...
With the custom tune, you'll gain even better/quicker throttle response & acceleration, stronger/harder pull, smoother & quicker power delivery throughout the rpms, etc... and sometimes, maybe even a little better gas mileage - if you can keep your foot out of it! hahaha...
absolute hp/tq gains are hard to predict... every vehicle is different... even if they're the same and have similar mods... location/weather, fuel used, elevation/altitude, etc etc all play a role... the same holds true for mileage gains - those variables, plus driving habits/style, how much highway vs. city driving, etc all make a difference.... you could gain no mpg increase, or you could gain up to about 3 mpg increase... tough to say due to the variables in play...
I CAN tell you that you will have a very noticable performance difference/gain over and above the canned preset diablo tunes...
I have gained people anywhere from 15-39hp, and 12-23lb. ft. torque, and 1-3mpg - over and above what the diablo tunes give you to start with... again, obviously mods, fuel used, etc all played a role in who gained what...
any questions, please feel free to hit me up...
and you can check out my site/tuning info here:
http://www.diablewtune.com
thanks!