I got the Flashpaq 4950, but the Cortex 4950 works the same. It worked on the VQ40DE and VK56DE engines used in Frontiers, Pathfinders, Xterras, Titans and Armadas. As I said, they cut their support for it at a certain year, but I forget what year, exactly. It can only tune one vehicle at a time and copies the factory tune to its database. If you return one vehicle back to the factory tune, you can use it to tune another Nissan, if you wish. It could read and erase DTC codes, allow you to record timed runs (1/4-mile, 0-30, 0-60, etc.), raise the speed and rev limiters, tweak base idle and ignition timing. The original software allowed for WOT restriction disable, but a software update removed that option for some reason. I believe there was also some basic engine monitoring, i.e. volts, RPM, O2 data, etc. You had several tunes, including tow, economy, 87 octane performance, 91 performance and 93 performance tune. It does NOT do any tuning to the automatic transmission. You can definitely feel the difference between some of the tunes and even 87 performance is an improvement over the stock tune. Economy tune turns it into a slug. It's pretty simple and straight-forward to use.