I have a Bully Dog GT. You can leave the factory tune settings in place, or reflash the ecm to performance, towing, or economy. It has a lcd display that allows you to monitor up to 4 gauges at once, with programmable alarms for temperatures. I always have the trans temp on there as it shows when the torque converter is locked. It can also read and clear trouble codes. It comes with a suction cup windshield mount, but I made a dashboard mount for mine. Edge CTS and diablosport make similar programmers. They plug in to the obd2 port under the dash.