The Car is currently stock. Tuning can only be done with engine off. iPhone app can monitor various vehicle stats while driving (only up to 3 at a time). You can get 0-60, 1/4 mile and 60-0 results when driving.
In comparison to sct/sf3
You can leave itsx plugged in, not visible unless inside vehicle
Don't have to search for tuner when you want to change tune
Provides additional data not displayed on vehicle gauges
Can store 10 custom tunes
Can get data results for 0-60 ,1/4 mile, 60-0
Worth it my opinion yes others may differ