Stand alone or self programmable ECUs are populair in racing cars. The ECU can be fully programmed by the user with delivered software from the manufacturer of the ECU. In most cases this is the most expensive way to tune a car. The ECU needs to be programmed to the engine and a wiring harness needs to be made. The price for these systems can be as low as paying for a tuning for your car to the cost of a second hand car.