To alter the engine timing, the ECU+ modifies the engine's crank and cam sensor signals. On all of the DSMs and the EVOs, the crank sensors generate the same type of signal, but there are four different types of cam sensor signals. With the ECU+, you can independently select the input (to the ECU+) and output (to the stock ECU) cam sensor type.
For most cars, the input and output cam sensor type is set to the same thing - whatever type matches the car year and model. For some important cases, though, these can (and should) be set differently.
The cam sensor on the '95 and '96 DSMs is mounted way down low on the motor. When the cam sensor breaks, you have to do the equivalent of a timing belt replacement job to fix it. With the ECU+, instead mount a '97 cam sensor up on top of the motor and wire it up. The ECU+ will convert that '97 cam sensor signal so that it looks (to the stock ECU) like a '95 or '96 sensor.
With the ECU+, you can easily swap to an earlier or later ECU. The ECU+ handles the cam sensor conversion seamlessly.
With the 6 bolt swap, a 1st generation DSM motor is swapped into a second generation DSM vehicle. The problem with this swap is that the 1st generation cam sensor has to be used, and the 1st generation cam sensor generates a different signal than either of the 2nd generation DSM cam sensors. The ECU+ fixes this problem with ease, and generates the exact cam sensor signal that the stock ECU expects. You'll get no misfire check-engine codes with the ECU+'s cam sensor conversion.
Don't confuse this feature with some common "hacks" to work around wrong cam sensor types. All of the four cam sensor types (1G DSM, both 2G DSM, and the EVO) are different, and any "solution" that involves moving plug wires around or using multiple sensors to work around misfire codes is just plain wrong. The ECU+ does this right.