The [megamanual] is the best introduction to do-it-yourself engine management we've found so far on internet.

It's the first step towards successful engine modifications, if you're not an expert, read it.

Similar ECMs - most have less functionality than VEMS, but better manual

These manuals get you acquainted with engine management in 1/15th of the time compared to reading forums or mailing list archives.

If you have read several manuals, please tell us your opinion which are the strengthnesses of each - or just in short: which one you liked in general.