Do I Need a Custom Tune
 

I'm looking to buy a Gryphon and was wondering if I can run one of the standard levels....or if I need a custom tune based on mods. I'm running a SI/DO Magnaflow Catback exhaust, K&N drop-in air filter, and slightly larger than stock tires. I absolutely want to see better performance with the programmer...one of my main priorities. However, fuel economy is a concern as well. Per my factory computer readout, I have gone from an average of 15mpg to 12 mpg as a result of the mods, although I'm not sure if my computer may be reading wrong since I put bigger tires on.

Any help is appreciated, thanks in advance.

With what mods you have you really don't need custom tunes.
But with the bigger tires the programmer will help "correct" your speedo.
Bigger tires most of the time equal mpg losses.
This time of year there is also winter blend gas depending on where you live. That also causes drops in mpg's.
A programmer with the canned tunes will help you and your truck.
:)

What mods WOULD require a custom tune? Cold Air Intake? What else?

Either way, I'm thinking the Gryphon over the Edge Evo may be a better solution just so I can get custom tunes down the road if need be. Do you agree?

Yes, I agree!
Custom tunes make any truck run better over the stock calibration weather or not it has mods.