One of the best mods I've done!
I lifted my 2015 Rubicon and installed 35" tires. I drove it for a week or so before buying the Flashcal. Once I installed it, I was shocked at the difference in just the recalibrating made! I wondered why I waited the week! I also like the extra features and the display is nice and easy to read. Also the added benefit if upgrading to the Flashpac is cool as well.