Plenty of EFI tuners available out there and virtually all handle A/F ratio in one way or another but I can't figure out which ones are THE ones that also offer adjustment of spark timing and duration.

Maybe a list somewhere? I can't find one anyway .

 

There are a few that offer timing adjustments, the TTS kit being one of the easier ones to use. The spark duration is built into the base maps and I don't think you can modify duration short of changing base maps. Duration is pretty much set long if I recall correctly.

 

Power Commander III will advance/retard ignition.