Open Source Engine Management: This can be the cheapest source of engine management available. In essence, you use a laptop, software, and a cable to reflash your stock ECU. Can be used to flash “staged maps” as a set it and forget it option or as a dynamic tuning tool either through tuners or by the end user. This form of engine management is best suited for people who:

Group 1:
A. Already have a good degree of tuning knowledge and understand the logic of the factory ECU (or have a strong desire to learn both).
B. Want to constantly tweak and experiment with their own tune. They actually enjoy the process.
C. May be changing/upgrading mods frequently.

Group 2:
A. Looking to get a custom tune from a professional but cannot afford or do not want to spend the money on license fees and/or hardware costs required of Cobb, Ecutek, etc. That is, they want their car to have a custom tune from a pro at the least cost. More and more professional shops are offering open source tunes and they can be just as capable as tunes from the commercial software.
B. Want an inexpensive (ex. XPT) or free (created by another user) OTS map. Might not go with EM otherwise because they feel it is too expensive. They are willing to learn the basics of logging with RomRaider to make sure the tune doesn’t have any issues with their car.

Those people where Open Source Engine Management would be a BAD choice (assuming they are doing it themselves and not a professional tuner):
1. Want the easiest to use, troubleshoot, and closest thing to “set and forget” EM solution.
2. Are computer illiterate.

Examples of Open Source Engine Management are RomRaider, formerly known as Enginuity, EcuFlash, and others.

Can the dealer detect my reflashed ECU (AccessPort/EcuTek/Open Source)?

YES the checksum of the ECU changes.
YES the dealer can easily read the checksum.

NO the dealer has nothing to compare the checksum against there are many revisions of the WRX ecu they all have different checksums. If the dealer had someway of putting this checksum into a database he COULD verify that the code had been modified but at this time he doesn’t.

The 05+ ECU and some of the 04s have the VIN in the ECU code. The current versions of reflashed ECUs only change the tables so the VIN will report when queried.

Bottom line: If you don’t want modifications to be detected, don’t modify the car.